Resetting Secondary iCloud Email

I have two apple emails, one that I use for my Apple ID/Account and another I use for emails. I can't login to my email account on my new iPhone, yet it's working on my MacBook. I've requested it to be reset and I was supposed to get something through by the 30th November but I haven't received anything.

Any ideas please - again, this is not my Apple ID/ Account but a secondary iCloud email address.