White screen of death when I'm trying to make a new post

I can’t see a good reason why any of the 10 plugins that I have all and all on my website started to malfunction out of the blue.
And what have the plugins to do with editing the permalinks?

The permalinks are actually the urls of the posts and in my case have the title of each post ( neither numbers or something else). Perhaps it got confused when I changed the title and changed the permaling simultaneously.

But this doesn’t make that much sense because it didn’t publish the post and then I deleted it and tried to post it again.

Left over of a deleted post and permalink in the database… that is what I’m thinking. It didn’t want to save something that it looked like it already existed… or something like this.
I don’t know how to write it right.