Hi All. Some of the users are experiencing an error when attempting to add an existing OneNote as a tab. The only time it is happening when it is a OneNote that has been generated by the Teams site. An example of this, is a user wants to have two different tabs referencing different sections of a OneNote Notebook. This is the error that is being spit out is attached to this post. I know this isn't a ridiculous request as it worked for me. Also, the users have tried both the desktop & web clients. Does anyone know what is causing this?