This may be poor adhesion and warping. Please show us the underside of that failed print.
Cheerio,
RE: Trying to print very simple print what could be the problem?
The obvious question is why you would even want to print it in that orientation and not with the flat side down, so no supports needed at all. I'd try that first and if the problem persist, we can look further. Plus, it's always best to attach a zip-compressed 3mf project file so we can see your settings. Without that knowledge, it's all speculation, and we might not be aware of what you might think was an innocuous change but one that had bad consequences. Having the 3mf will at least allow us to rule out any settings-related issues.
Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...
RE: Trying to print very simple print what could be the problem?
Well, for this photo I paused the print, supports are needed both sides, first tried printing the other way but the visable side (with supports) was really bad. So I tried printing it the other way around, like in the photo I sent.
I have printed Manny times with the prusa mk4s using always the prusa preset 0.2 mm speed , this problem never happen before.