HTML error on loading images, again

Dear friends,

suddenly I found that I was unable to load images to the gallery. The WP gives me HTML error. I looked in the forums about this problem and I found solutions of 6 and 4 years ago (to revise the size, to check the name, to check the pluguins, to increase the memory to 64MB, etc.), but no one solved my problem. I guess that the problem started with installed a pluguin referred to gallery manage, but this plugin already is uninstalled, as well as the whole WP (4.3.1) has been re-installed.

Please, I’ll be grateful if any of you could advice me. Also notice that I’m not a programer, so I can’t apply PHP programming solutions.