Meil don`t syncing only inbox folder

Hello, I have a problem with synchornization (outlook / gmail). I have 30 e-mail accounts on one of the hosting plans. Only on one of them there is a problem with synchronization, the main folder (inbox) is synchronized, but additionally created folders are not. I transferred several mail from another domain to the mail folder in cpanel. The other mailboxes on this domain don't have this problem just on this one. I delete all new folders on this meil. Create new folder xxx > create forwarders to folder xxx > and e-mail on laptops go to folder xxx but on phone ( gmail/outlook ) it`s not syncing . When I open folder xxx on (gmail/outlook app in phone) sync is start.