2015 turbo throwing PO620 after installing new alternator?

I replaced my old alternator because it wasn’t charging. the car felt normal the day of the install. but this morning the motor is low on power and throwing a PO620 anyone have this same issue? i have my catch can over my strut tower ground cable as most do. could i have not grounded the motor correctly? Control module is getting steady 14 volta and the battery is steady and charges when rpm increases