I can’t send mail on my iPad’s mail app.

I can’t send mail on my iPad’s mail app.  I can send email on my iPhone, my Mac, and on my Microsoft Exchange web page.

So I’ve been looking for settings that are different and trying various passwords I have tracked down.  I see in Keychain lots of accounts with smtp (most of which I no longer use). I see most of them have either the password for GoDaddy or Microsoft Exchange (which GoDaddy uses).  I have been trying variations of these as my SMTP outgoing mail server.

My iPhone has as my primary server “iCloud SMTP Server”, without a User Name or Password, SSL, Authentication=Apple Token, port=587.  

It has other SMTP servers as well, I have tried changing them as well. Changing them fails much more quickly.

I tried entering that on my iPad Air (5th generation) 15.6.1, but after trying to verify, it tells me it’s not responding.  I found https://www.saleshandy.com/smtp/icloud-smtp-settings/, and tried server address map.mail.me.com, but that also failed to verify. Finally had to kill the process.

I tried iCloud Mail server settings for other email client apps - Apple Support, with Server name: smtp.mail.me.com. I tried 3 different passwords.

How do I find which address and password my iMac or iPad are using and get them on my iPad?