plugged in, not charging + screen goes black for seconds

I have a dell latitude E5440 Windows 10. A couple of days ago I noticed that my battery was plugged in but not charging. I plugged it in another building and in a certain time (probably half an hour) it started charging. The same has happened in all plugs. I updated BIOS. I checked the setup (pressed f2 on startup) and the AC adapter wasn't being recognized. Yesterday it started charging immediately. Checked the setup again, not it says: AC adapter - 90W. However, whenever the laptop is plugged in (and this has been going on for a couple of days now), the laptop sometimes flickers, the screen goes completely black or has multiple colors. This mostly happens when I press something, but not necessarily. My ac adapter is also plugged into a US to EU power adapter, if that matters. I am afraid to damage the laptop. Do you think there's something wrong with the AC adapter?