Need help configuring email...

Last week I was assigned a new webmail email address for a new business I'm starting with a few colleagues... I was able to configure and gain access to the account on my mac and iPhone using the apple mail client.

On friday, we tried an experiment and migrated over to Outlook (which I configured on my mac with the Outlook app).

Everything was working fine...as expected, my mail was not accessible through my iPhone or Mac (using apple mail client)

Today, we decided to nix the experiment and dump Outlook... everyone is going to use their own email client.

Now, my iPhone and Mac Apple Mail apps won't work... they are telling me "unable to verify account name or password"

If I try to send a message, I'm told: "Connections to host mail.xxxxxx.com on the default ports failed. Select a different outgoing mail server from the list below or click Try Later to leave the message in your outbox until it can be sent"

This is driving me crazy... it was working fine a few days ago.

Anyone have any insight?