We found the issue from our users about the folder and sub folders.
We found that some of the parent folders are missing on the server level. therefore, when our users subscribe the folder, it will give server error (refer attach1)
Then, We have checked on inbox folder via webmail and found that the missing folder on the server showing in webmail as a gray out folder. (refer attach2)
for the example, the resource we found is folder ".02 test level2-2" is missing, we found only ".02 test level2-2.02 test level3" exist on the server (refer attach3)
This issue fixed by re-created ".02 test level2-2" folder (refer attach4)
We can't determine what's the root cause and we willing to know how this issue occurs?
Again, we have confirmed our users can't login to the level server and delete the folder directly on the server, They can access only webmail and outlook.
Please let us know if anyone has experienced this issue before.
Thank you in advance.