Cannot send emails for about 5 days now

We are unable to send emails from any of our email apps on our Android phones.  It appears to work only for about 3 hours once a day and then goes down again and I can tell when it's down by by not changing any settings on the outgoing server but it's simply gets a 421 error that comes back. If the 421 error doesn't occur then I know that it's working fine.  When is this going to be fixed by Comcast?