Automatic updater results in internal server error 500

I wanted to use the automatic updater to update phpbb from 3.2.0 to 3.2.1

as i have some modification made to some templates

I set the style on boards default e.g: Prosilver, english language, and set the spamcountermeasure to Q&A.

Uploaded the folders from the unzipped zip package to the root of the forum

then i go to install/

I see the introduction screen, but as soon as i click on the update tab

I got a white screen.

Then i wanted to go back to the forum using it's url ,but again white screen.

Even when i manually deactivated all the extensions and purged the cache.

still white screen.

I removed the install and vendor folder from the server and uploaded a backup of the vendor folder back, still white screen.

I eventually removed everything and set the forum back to it's normal state at version 3.2.0

I Looked in the server error log, nothing to be found of any internal server error.