When you install the plugin, you go through the basic setup of the plugin by answering a series of questions - this setting affects the subsequent work of the plugin.
The good news is that is possible to fix it yourself:
You need to go to the link, where all the instructions for setting up roles between users are written:
(https://imbachat.com/en/blog/post/how-set-user-roles-user-role-editor-plugin)
And check if you configured everything correctly according to your wishes and requirements for the work of the plugin chat.
If you still have a problem, please contact technical support at the postal address support@imbachat.com and give a detailed description of your problem and attach screenshots in an appeal to technical support. Then our specialist will be able to understand in detail what your problem is and help you fix it.