NicoL

Also I'm still on DSM 6.2.4-25556 (not 7.0) It should be interesting to know how it ends up with this issue (same error code with sync with NextCloud). Was it solved by a fix on the Enpass side or by everybody following this advice ?

Same error here since I update Synology Webdav Server Package from 2.4.0-0062 to 2.4.1-0108 (releases notes). While waiting for a solution either on Enpass or Synology side, I've downgraded my version from 2.4.1-0108 to 2.4.0-0062 and it works again like a charm.