Outlook is Really Glitchy with My Comcast Email

Hi,

I am having all sorts of issues with trying to use Outlook on my Comcast email.  Now, when I send emails, it will often send the message, but completely blank out all content.  Other times, it send the message, but add all sorts of nonsense characters to make it really hard to read.  When I contacted xfinity, they just pointed me to the instructions on how to connect to Outlook, and I think I followed all the recommended steps.  Any suggestions would be welcome.