Can No Longer Send Email To My External Email Account

I used to be able to do the following with no issues.  Now it fails.  I am paying a subscription to use Outlook.com, and I do not use it for free.  I am finding no way to get any support for something that I am paying for, and it is now not working as it used to.  How do I get support now?

I take photos using my Andoid phone to then send that photos I just took to my non-Microsoft external email address hosted by ZOHO email.  As I wrote above, I used to be able to do this with no issues.  Now all attempts to send email with JPG attachments to my ZOHO email address results in a failure:

Your message wasn't delivered because the recipient's email provider rejected it.

I am paying for ZOHO email, so I contacted support asking why my email is being rejected.  Support troubleshooted this to find that they are not even receiving the email.  Microsoft is not even sending it.  This used to work, but now it is broken.  How can I get support for this?