Free email certificate and encrypting in iOS 12

Hello.

I finally got my free email certificate installed and working on my Mac.
Now I need to get them working on an iPhone Xs running OS 12.1 certificates installed and I can sign. but can’t encrypt.
If I encrypt an email on the Mac. I can see it on the iPhone with no problem. it says is signed and encrypted. I can also reply with encryption on.
Just can’t encrypt on a new message

Thanks in advance.

I guess I should have clicked. but it was late and I was tired.
Same rule applies like it does on the Mac mail app. you can’t encrypt email to yourself. So it works. as long as your emailing someone else.