@al_3
I can’t see your screen and the exact steps you are taking. If you have a standard iOS developer subscription then the provision portal will allow you to create 2 certficates, a developer certificate and a distribution certificate. Don’t waste your time dick’n with the developer certificate. It will expire in 3 months after creation. The distribution certificate is good for 1 year. So pay very close attention that when you are on the certificate page of the provision portal that you select the distribution tab before uploading your csr.
If you have an existing certificate that you want to remove, you must Revoke it. Once revoked you can request a new certificate using your certificate signing request (csr) file. Recall that you will have a companion private.key file; don’t loose it.
Go ahead and delete all your provision profiles as well as they will be kaput as soon as you revoke the certificate they are associated with. Lastly, clean up your disk of obsolete profiles, certs, csr, pk files. I keep all of my files in a well known location. And never share your private.key file; threat it like a like a password.