"Debugging and troubleshooting", "List of MyChat Client errors", "Error #0290".
 
Error

Error #0290: incorrect ID (XXX) specified in the user personal group
 

Error description

When working with personal groups you specified an invalid ID, or ID that does not belong to your personal user group.
 

Problem solution

If you work with MyChat via API or directly using an open network protocol, change the transferred data.