Do my PrimeGaming and Ubisoft accounts have to have the same email address?

I registered with my email address on the PS4 in R6 and when I saw that you get free skins when you log in with PrimeGaming.

My sisters have AmazonPrime and therefore also PrimeGaming, so I asked them if they could briefly log into AmazonGaming on my PS4. They said yes.

Everything went well, only at the end it said Connect game account, I pressed it, then it said Connect your Amazon and Ubisoft account. I pressed Connect and the message This function can't be used came up.

No, actually the email addresses don't have to be the same. Are you already connected to another account? Try again, otherwise nobody will be able to help you