If you are getting the bouce back email with the message as below
Error :-

SMTP error from remote mail server after MAIL FROM: SIZE=5000000:
host mail.domain.com [xxx.xxx.xxx.xx]: 552 Message size exceeds maximum permitted

Follow the steps given bellow :-
Increase the message size limit set.
1. Login to ypur server with the ssh access and root user
2. Edit exim.conf files.
[root@server ~]# vi /etc/exim.conf
3. Search for “message_size_limit” and change the limit.
message_size_limit = 7M
I have used 7 megabytes , you change change 5m to whatever size you would like.
Thats should resolved the issue 😀