Restart the eye tracker:

• Switch off the eye tracker.
• Disconnect the eye tracker.
• Reconnect the eye tracker.
• Switch back on the eye tracker.
• If an SR Eyelink has been used a fixed IP address will have been set on the network adapter. This needs to be changed back to dynamic to work with Tobii. Go to Network Adapters, right click, etcetera.
   

1. Restart EPU:
   • Switch off EPU.
   • Disconnect the power cord.
   • Reconnect the power cord.
   • Switch on EPU. 
      
2. Check cables: USB cable from eye tracker bar to EPU and the ethernet cable from EPU to PC.
   
   For the X3-120 the USB cable can be replaced, labsupport has them in stock. The USB cable of the X2-60 cannot be replaced, as it is attached to the eye tracker bar. If the issue seems to be related to the USB cable of an X2-60, the eye tracker needs to be sent to Tobii for repairs.
   
   Note: When the Eye Tracker Manager or Browser is only showing the EPU number (starting with EPU instead of e.g. X3-120) it is fairly likely that the USB cable between the EPU and eye tracker bar is the issue. This can further be tested by plugging in the eye tracker bar directly into the PC. When the USB cable is fine, the eye tracker should appear in the Manager or Browser. Finally, replacing the USB cable (if possible) should provide a further answer.
    
3. Happened once with a X3-120 eye tracker: The firmware version of the eye tracker bar was different than the firmware of the EPU. Unknown how this happened. Could be fixed by Tobii with remote session.
    

1. Check if Tobii eye tracker can be found in Tobii Eye Tracker Manager.
    
2. If the eye tracker is found in the Eye Tracker Manager, reinstall Bonjour 2.0.2.0 (admin rights required, contact labsupport for installations on lab PC's). If the eye tracker is not found in the Eye Tracker Manager, check the solutions mentioned above.

Note 1: The newer generations of Tobii eye trackers (e.g. Tobii Fusion) are not compatible with the Tobii Eye Tracker Browser and Tobii Pro Studio.

Note 2: When Tobii Pro Studio or E-Prime 2 does not need to be used, one can just use the Eye Tracker Manager for setting up the eye tracker (screen alignment). Connection with Tobii Studio, the Browser, and E-Prime 2 is not necessary for an eye tracker to function with other software packages.
 

1. Check whether the correct eye tracker number is specified in E-Prime:
   Go to Edit ⇒ Experiment ⇒ Devices ⇒ TobiiEyeTracker. In E-Prime 3, the eye tracker can be specified in the Eye Tracker drop-down menu. In E-Prime 2, the eye tracker serial number needs to be looked up in the Eye Tracker Browser, then copied and pasted in the IP Address/Name field in the TobiiEyeTracker device in E-Prime.
    
2. Check whether the eye tracker can be found in the Eye Tracker Manager (E-Prime 3) or Browser (E-Prime 2) and check the solutions above.
    

1. Check the serial number. The serial number should be specified in an inline at the beginning of the task:
   
   from pygaze import settings
   settings.TRACKERSERIALNUMBER = "X3120-XXXXXXXXXXXX"
   
   The serial number of the eye tracker can be found in the Eye Tracker Manager.
    
2. If serial number is correct, try running the task again. For reasons unknown, this error just pops up from time to time.
    
3. Check connection with eye tracker in the Eye Tracker Manager . If the eye tracker is not found in the Eye Tracker Manager, check the solutions mentioned above.

Tobii Pro Lab gives error when trying to start the calibration:

Someting went wrong.

Something went wrong when communicating with the eye tracker. If the error persists, please try restarting the eye tracker and the application.

Make sure the eye tracker is mapped to the screen by doing the Display Setup in the Eye Tracker Manager.

Restart the eye tracker and Tobii Pro Lab.