No upload, no creation of new issues, no access to some setting tabs possible

For one week now I can neither upload new submissions anymore, nor create new issues or access to the Website setting pages Languages, Plugins, Announcements and Navigation Menus. Below you can find some screenshots.
I already did everything recommended in the topic The file could not be uploaded or revised - #8 by monicalp, but it didn’t help.
Also i can not apply the advices from the topic Immersion Theme: create issue problem (Failed Ajax request or invalid JSON returned.), because i can not access the Plugin Settings.
Do you have any other suggestions what my problem could be?

Im working on Windows 10 and OJS 3.1.1.4.

grafik
grafik
grafik

Hi @knothe

I recommend you look in your PHP or web server error log, for lines marked as Fatal Errors.

Cheers
Jason

Hi @jnugent,
i can not find any fatal errors!

Maybe look at your php logging settings in php.ini and make sure things are enabled? Not getting logs when you get blank screens is quite unusual.

Cheers