Why do I have colored dots on my print?
Colored or black dots can have two possible causes:
Sublimation paper issues:
Some papers cannot handle the combination of expansion & pressure on the edges of the panels of the paper. As the paper is coated, the edges of the panels scrape away the coating+ink on the paper, which in turn fly around during the sublimation process (gassing). Those fibers (with ink on it) will fall somewhere on your panel.
This happens usually when you have bigger pictures with a lot of contrast (darker/lighter images). You can solve this issue by using other sublimation papers.
Strands of cloth or fabric from clothes:
Often colored dots come from small strands of cloth or fabric from clothes or microfiber cleaning cloths that fall in between the surface and the transfer paper before pressing. Take extra care to wipe down and inspect your panel immediately before pressing it to prevent colored dots.