Can't send email - what is wrong?

Three weeks ago I received a msg on my phone from Microsoft saying they suspected my email account had a security breach and prompted me to reset the password. After changing the password for my email online, I proceeded to update the password in my iphone for the same email account.

After doing this, I can receive and read all email, however I can't reply to or send any new emails. This has always been my sympatico account setup with a POP server. I have deleted and added the account again - same problem. I have also set up the email on the iphone under outlook, this solved the problem, however now when I delete an email from my iphone, it deletes it on the server.

I have a couple questions:

1) Can my POP account for sympatico be resolved on the iphone and work as it did prior to changing the password?

2) If I the POP cannot be resolved, how can I setup the outlook account (under sympatico address) from deleting my messages from the server?