I have and Ender 3 and have no trouble printing PLA. Lots of good quality prints.
I just got a spool of PETG and cannot get it to work. The main problem is that it does not adhere to the bed. The filament comes out of the nozzle well, and prints the test strip down the side of the build plate but when it moves to the center and tries to begin the print the filament just balls up around the nozzle. I have tried adjusting the bed level, have tired different temperatures for nozzle and bed (235, 240 .250 nozzle, 60, 70 80 bed). I have turned off the fan. I have used blue tape on the bed. Nothing seems to work.

Any suggestions?