Unable to Send Emails from ZOHO CRM - Error Message and Troubleshooting

Unable to Send Emails from ZOHO CRM - Error Message and Troubleshooting

Hello,

I am a user of ZOHO CRM, and I've been trying to send emails from ZOHO CRM for the past two days without success. The error message I am receiving is as shown in the screenshot below.


I have performed the following checks to investigate the issue:
  1. Changing the recipient email address to a different one within the same domain allows me to send emails successfully. For example, changing from aaa@example.com to bbb@example.com works.
  2. I have increased the mailbox storage capacity to ensure there is ample space, but this has not resolved the issue.
  3. When I hover my cursor over the yellow exclamation mark, it behaves as shown in the screenshot.

I would appreciate any assistance or guidance you can provide to help me resolve this issue. Thank you for your help.

Best regards,