Charter.net outgoing email issue with Apple Mail or Outlook

I have the latest Mac Book Pro (13 inch, 2017) running the latest version of High Sierra 10.13.3. I use Charter.Net as my mail provider and cannot send mail from either Outlook or Apple Mail. The outgoing port is configured as Port 587 with SSL. I called Charter and they said it is a known issue with Mac Products. My email works just fine with my iPhone and iPad. Is anyone familiar with this issue or developed a "work around"? I would appreciate any feedback.