This happens to my map about 20% of the time. One day it works fine, the next day none of my coworkers can print.
The map is regularly updated using Pro/Save Web Map. We use OSM as basemap. AGOL and Experience Builder. Using print widget, it will spin for a bit and then red X.
Sometimes, clearing the cache or switching browser helps. Occasionally, deselecting layers or changing basemap helps. This seems to be a bit of a glitch or something catching. I wish there was more documentation or a way to clearly fix this without completely republishing and still potentially facing that issue on the next republish. Currently, struggling to find a fix that doesn't include modifying map.
Looked at Dev Tools and found an error when print widget was trying to execute, potentially due to map load but it was working fine yesterday so not sure how anything could have changed.