I just moved my server. Dovecot version 2.3.19.1 (9b53102964) After the transfer, I deleted the indexes and caches and rebuilt them. One of my users is experiencing slowness when send/recevie all his folders. The user has about 250 folders with a maximum depth of 3. The volume of emails is about 13 GB. Outlook wants to receive all email folders in every send/recevie all folders. Outlook 2019 and Windows 10. We connected to other users with his Outlook and we don't have this problem. We also tested with another device and same user and we have this problem. Another user with 100 folders also reported slower sync speeds after transfer server. Outlook 2019 and Windows 10.

I just moved my server. Dovecot version 2.3.19.1 (9b53102964) After the transfer, I deleted the indexes and caches and rebuilt them. One of my users is experiencing slowness when send/recevie all his folders. The user has about 250 folders with a maximum depth of 3. The volume of emails is about 13 GB. Outlook wants to receive all email folders in every send/recevie all  folders. Outlook 2019 and Windows 10. We connected to other users with his Outlook and we don't have this problem. We also tested with another device and same user and we have this problem. Another user with 100 folders also reported slower sync speeds after transfer server. Outlook 2019 and Windows 10.