Case 1 (Less)
Cause: DNS issue
Solution: Check /etc/resolv.conf for correct record. You can use the nameserver below:
nameserver 8.8.8.8
nameserver 4.2.2.2
Case 2 (Common)
Cause: An email account spamming and causing the email counter to reach limit. /etc/virtural/usage/<<user>>
Solution:
1) Check /var/log/exim/mainlog for spammer
2) Change that email account password
3) Reset counter. Replace <<user>> with directadmin username.
echo "" > /etc/virtual/usage/<<user>>
