There are no serial numbers associated with Adobe CC.
In case you still get the pop up for serial number, please refer to the help document below:
You may also try to check your host file for any Adobe blocked entries.
In case there are any blocked Adobe entries, please delete them and then save the file.
This wasn't very helpful. Also, when going to my account and going to "Plans & Products", it says We are unable to load all your plans & products. Please try again.
The Adobe Id on the forums has no active membership/licenses under it.
Please confirm me if you have subscribed under any other Adobe ID.
This is the ID I linked when I purchased my CC subscription via Amazon on July 15th.