Today I discovered that the PHP exec function is required, when it was included in the list of disable_functions this error message was generated:
php occ onlyoffice:documentserver --check
Error connection: Error occurred in the document service: Error while downloading the document file to be converted.
However I can’t now reproduce this behaviour by adding exec to the PHP disable_functions setting so something else must have been preventing it from working…
php occ onlyoffice:documentserver --check
Document server https://onlyoffice.example.org/ version 6.4.0.121 is successfully connected
Unfortunately, there’s no documented list of php functions. Moreover, our connector doesn’t use exec function. I think this is the reason why you couldn’t reproduce the situation.
Probably there was something else in your first test that influenced the situation.