File Versioning Issue

Hi, I am having some issue in nextcloud which is listed below,

Issue :- 1) User A shares file to user B. User A changes locally in file and again uploads in same location. Cloud creates version of that file. Now shared user trying to download that file, cloud server respond with Error 503(Service unavailable).

issue :- 2) As user restores particular version of file, user not able to download latest file, cloud server respond with Error 503(Service unavailable).

issue :- 3) Collaboration file not syncing with original file while file is open in collaboration mode. (I am downloading file while file is open in co-editing i.e. collaboration mode. Changes not reflected in downloaded content.)

Any help from anyone is most appreciated.