I'm trying to help to person who wants to send email with size 3MB attached file and getting error saying '' You are unable to send email with that size because of internal smtp server error. Ask your network admin or your ISP.''
The person used to send emails with that size and even bigger but not now. he is using Outlook POP3 client and Exchanhe SRV is hosted by his ISP.
I tried a lot of solutions as made attempts to speak to his ISP as his ISP might be put email size restriction for all outgoing emails but couldn't get reply. Then split up his Outlook from using his Norton Antivirus as it scans all his outgoing emails, run Outlook in safe mode and hundreds solutions with no success.
Any advice what else I can do next.
Thank you in advanced!