Unable to create press OMP

During installation I get a 504 Gateway Timeout (tried increasing timeout values in php.ini to double their default values for the installation, but that did not seem to have any effect). Site still seems to be accessible, but when trying to create a Press I get a notification saying “{$name} was created successfully” but no press is created. Is this a permission error of some kind? Can’t figure out where this goes wrong. The database looks ok, tables access_keys → versions are there. The user we created is in the users table and sub-directories have been created in the files folder, but are empty.

Additional info. Seems like OMP is not writing to the database. I can enter info into the Site Setup Info tab, but it is not written to the database, even though a notification pops up telling me it has been updated successfully. Entering it directly in the database brings it up in OMP correctly.