Accesing email on android

I can access outlook on the desktop with entering my comcast credentials to the yahoo option and that works.

Having difficulties accessing on android, adding a new account with yahoo keeps telling me try a device you've signed in with before

That actually sounds like more of a security/sign-in issue rather than one of the protocol issues we see more, @MattJ1.  Are you by chance connected to a VPN? I would recommend reaching back out to yahoo again sometimes a second try is a charm. Once an account has been migrated to yahoo we do not have any tools or very much insight to resolve issues. 

They seem to think I need a cell phone they can text me on which I don't understand has anything to do with. I let them view everything as I was doing it.

It sounds like Yahoo may be attempting to perform multifactor authentication, this is a security measure to ensure that only you have access to the account. This is a pretty normal practice and something most companies recommend doing. You could ask Yahoo if there is another way to confirm your identity, but I am unsure if they have an additional path. 

@XfinityJustinM​ I gave them another email, it doesn't ask for any other authentication, it just tells me to use a device I've used before which doesn't help me logon using any of my other android devices. The lack of authentication doesn't impede my progress on the web platform on desktop or outlook desktop. I get the same prompt to use a device when trying to access the web platform on my android at yahoo.com. No request of secondary authentication there either