This guide will let you know how to fix the PS4 Error E-8210604A. You have to follow the simple steps in this guide to fix the error.
First, you will need to go to Settings and click on the Account Management option. Then go to the Account Information option, and it will start loading, as shown in the image below.
After loading, you will see different options of account information, you have to change youR Sign in the Id email address to a different one, and you can also use your Gmail account, which will change your PSN sign-in email address. If you are doing it on your PC version, you can also do it by changing your email address. If you cannot do it, you have to create a new PSN account to change your Sign-in id email. It will fix the error.