it can be one of 3 things.
Bed distance from nozle, Bed temp or nozzle temp.. I run my temp at 236/ 82 for petg .. and have a bit more distance then for pla. the bead needs to lay down onto the bed and not squished like you need for pla....
hope this helps
I run at 230/68 on the glass bed for PETG and what @Erica-Renee said about squish is correct.
It also depends on the printer.
You could also try aqua net unscented mega hold. I don't need it anymore since I got my leveling/temps down pat but it works really well while you are learning.
