Troubleshooting Connections

If Rostoc fails the connection test or can’t connect your Machine, work through the steps below. The message Rostoc shows tells you where to start.

Start with your symptom

Symptom	Where to go
The connection test fails, or Rostoc shows Port Not Found, Port Busy, or Device Not Responding	What the connection message means, then the sections on this page
Connected, but no readings — temperatures missing or the live Curve stays flat	Connected But No Readings
Live readings lost their colour — numbers show but look greyed out	Greyed-out readings and degraded status
Machines shows an amber status dot or “Telemetry degraded”	Greyed-out readings and degraded status
It worked before, then stopped after a restart or router change	Router Changed The Machine IP
The connection drops in the middle of a roast	If the connection drops during a roast
An Aillio Bullet shows “Waiting for your …”	When Rostoc is waiting for your Bullet
Rostoc says a Machine has no port on this computer yet	Choose the right port, then see A Machine’s port on each computer
Live readings work, but a control is missing or rejected	Machine controls
A brand-specific setup problem	The brand guide’s own troubleshooting: Kaleido, Probat, Santoker, Aillio Bullet

If live temperatures work but a direct control is missing, rejected, or marked uncertain, the connection may still be healthy. Telemetry and direct control are separate capabilities. Check the exact model in the Machine catalog and follow the status and safety guidance in Machine controls.

What the connection message means

Message	What it means	Start with
Port Not Found	The port in the Machine’s settings isn’t there. Usually the cable is unplugged, or the port changed.	Check the cable and port, then pick the port again in the settings
Port Busy	Another program, such as other roasting software, already has the port open.	Quit other roasting software, then connect again
Device Not Responding	The port opened, but the roaster never answered.	Check that the machine is on and past its startup, then check the settings against its manual
Device Not Reachable	Nothing answered at the IP address and port in the settings.	Network connections

On Windows, Rostoc recognises a port held by another program whatever language your computer runs in. On a Mac, Rostoc does not open a port that another program has locked, and shows Port Busy. A program that uses the port without locking it can still let it open, and the roaster then reads as not responding. If you see Device Not Responding on a Mac, quit other roasting software first.

USB / Serial connections

1. Check the cable and port

Try a different USB cable — data cables and charge-only cables look identical but behave differently
Try a different USB port on your computer

2. Check that the machine is on and ready

Most machines need to be fully powered on and past their startup sequence before Rostoc can connect
Some machines need to be in a specific mode (e.g. “idle” or “data output on”) — check your machine’s manual

3. Check for driver issues (Windows)

Some machines require a USB-to-serial driver (CP210x or FTDI)
Open Device Manager and look for any yellow warning icons under “Ports (COM & LPT)”
Download the driver from your machine manufacturer’s website

4. Choose the right port

On macOS and Windows, the port list leads with USB ports. Bluetooth serial ports sit behind Show all — open it only if your machine connects through a Bluetooth serial module
A new Machine starts with no port (None selected). If Rostoc says the Machine has no port on this computer yet, click Choose its port and pick the one the Machine is plugged into
Each computer keeps its own port for a Machine. On a second computer, the port your first computer uses is marked Recommended in the list, or Not on this computer when this computer has no such port. See A Machine’s port on each computer

5. Quit other roasting software

Only one application can claim a serial port at a time
Close any other roasting software that may be connected to the same machine

Network connections (Ethernet and Wi-Fi)

1. Scan the network for the machine

Open the machine’s connection settings and click Scan network under the IP address field. Rostoc checks every address on your computer’s local network for a machine answering on the connection’s port and lists what it finds — if the machine appears, pick it and the address is filled in. The scan runs only when you start it, never in the background.
If nothing answers, check the port named in the drawer’s message: the scan asks about one port only, so a machine configured for a different port reports the same silence as a machine that is off. Correct the port, then scan again.
If the machine still doesn’t appear, confirm its IP address the direct way: from its display, your existing setup, your router’s device list, or the machine documentation. If the address changed after a router restart, see Router Changed The Machine IP.

2. Check that the computer can reach the machine

The computer and machine must be on the same local network — or, for a direct Ethernet cable, the computer needs a manual IP address in the machine’s subnet
Enter the machine’s own IP address. 127.0.0.1, localhost, or an empty address points at the computer running Rostoc, not the roaster, so the connection cannot succeed

3. Check for competing connections

Close other roasting or logging software; many machines accept only one connection at a time

4. Check the network path

Firewall or network security software can block local machine traffic — allow Rostoc when the operating system asks
Prefer a wired connection over wireless bridges for production roasting; dropouts on a bridge look like machine faults

Bluetooth connections

1. Unpair and re-pair

Remove the machine from your computer’s Bluetooth device list
Put the machine back into pairing mode and let Rostoc discover it fresh

2. Check Bluetooth permissions (macOS)

Go to System Settings → Privacy & Security → Bluetooth
Make sure Rostoc is listed and allowed

Greyed-out readings and degraded status

A machine can stay connected while its readings stop arriving. Rostoc shows that state rather than letting stale numbers pass for live ones.

Readings lose their colour. When a stream stops updating, its value fades to grey in both the main window and Roast Studio. The number you see is the last one the machine actually sent, not a current reading.
The status says why. Machines shows a warning status reading Telemetry degraded, followed by what Rostoc observed — for example, telemetry silent for five consecutive polls.
The machine is not disconnected. Rostoc keeps reading and the readings come back on their own the moment the machine answers again. Only a longer silence disconnects the Machine.

This usually means the machine stopped answering rather than that anything is wrong with Rostoc: a roaster busy with its own controller, a crowded wireless link, or a probe that has stopped reporting. If it clears on its own within a few seconds, nothing needs doing. If it persists, treat it as a connection problem and work through the section for your connection type above.

If the connection drops during a roast

Keep roasting from the machine’s own controls first. The roast never depends on Rostoc staying connected, and the machine keeps running exactly as you set it.

What Rostoc does when readings stop mid-roast:

Short interruptions recover on their own. Rostoc retries failed reads automatically, so a brief hiccup of a second or two usually passes without you noticing.
Displayed temperatures hold the last received values and fade to grey until fresh readings arrive, so milestones you mark during a gap keep a usable temperature.
Rostoc says when the machine stops answering. Within a few seconds of readings stopping, a banner at the bottom of the window starts with your Machine’s name and reads is not responding — check that it is on and connected. Still trying…. The connection is still open, so the readings come back by themselves as soon as the machine answers.
An Aillio Bullet is waited for. Rostoc never gives up on a Bullet: when it goes away, Rostoc watches for it and connects again when it comes back. See When you switch the Bullet off. The reconnecting and could-not-reconnect banners below are for every other Machine.
Rostoc tries to reconnect by itself. If the machine stays silent, or its USB port disappears, Rostoc closes the connection and reconnects. The banner then reads connection lost — reconnecting, followed by the attempt number and a countdown to the next try. While a roast is recording, it adds recording continues; telemetry gap in progress. Rostoc keeps trying on its own, so you don’t have to do anything. Click Retry now if you want it to try straight away.
You can close the banner. From Rostoc 0.4.5, the banner has a close button. It stays closed while Rostoc keeps retrying. It comes back only if the situation changes: every attempt fails, or the connection drops again later.
When every attempt fails, the banner says so. It changes to your Machine’s name followed by could not reconnect — connect manually from Machines, with a Retry button. This is the point where you reconnect the Machine yourself.
The recording keeps running throughout. The Batch clock is not reset, so anything you mark stays at the correct roast time. The missing stretch stays as a gap in the Curve; readings from before and after the dropout are kept.

What to do:

Make your roast decisions at the machine. While the banner says not responding or reconnecting, leave it to Rostoc.
If the banner says could not reconnect, fix the physical link when it is safe to look away from the drum: reseat the USB cable, or restore the network. Then click Retry, or connect the Machine from Machines.
Once readings come back, the Curve carries on at the correct roast time.
Don’t abandon the Batch because of a gap. Finish the roast, mark Drop, and save — everything that was recorded stays with the Batch.

If dropouts repeat, prefer wired Ethernet over Wi-Fi or wireless bridges, and work through the connection sections above after the roast. A Machine that drops readings when it is asked too often can also be read at a slower pace: see How often Rostoc reads your Machine. Clicking Send Feedback after a dropout shares Rostoc’s recent logs with Rostoc support — see below.

Still stuck?

If none of the above helps, reach out. Include your machine model, operating system version, the connection type, and the exact error or control status Rostoc shows.

You can also send a report from the app after a failed connection: open Settings → Preferences, and under Support & Diagnostics click Send Feedback. Describe what happened and click Submit Feedback: Rostoc sends your note with recent logs to Rostoc support. Nothing is sent before you click it. For Nucleus Link, the guided connection test has its own Send Diagnostics button.

If telemetry works but a control is missing or rejected, see Machine controls and check the exact model page in the catalog.