I think I read somewhere that some people experienced trouble with their skis not remembering their keys if the battery was removed for some length of time. Sounds like your ski has either lost your key information in its memory OR that is not the right key for your machine.
My personal experience (2017 Spark) was a sunken ski, taken out of the water, lost primary NORMAL key, completely rebuilt with a new hull, no battery installed for over 6 months. Put everything back together, found the Learning key, woke up the ski and installed the key.....ski recognized it immediately and re-started. I bought 2 new keys from Seadoo and my dealer programmed all 3 keys to the ski, making them all NORMAL keys (no more Learning key)...only charged me $16.00 for the re-programming. You only need the ski, key(s) and a laptop (with Seadoo software and the USB cable to talk to the ski, took all of 5 minutes in the parking lot).
Good luck.