"Debugging and troubleshooting", "List of MyChat Client errors", "Error #0324".
 
Error

Error #0324: group identifiers list is empty
 

Error description

When deleting one or more groups in the custom user menu, it turned out that the list was empty.
 
Problem solution

An error may occur if you use a third-party client to work with MyChat Server or make your own implementation of MyChat open protocol. You should check if you specified everything correctly in the  cs_remove_groups_from_custom_menu.