Timeout occurs when defined value is reached in each phase as bellow:
1. When MTA doesn't exist or there is no return from the connect system call the below error message will be issued:
421 4.4.0 [internal] no MXs for this domain could be reached at this time
2. When there is no return from 220:
450 4.4.1 [internal] Connection Timed Out
3. When there is no return from EHLO :
450 4.4.1 [internal] Connection Timed Out
4. When there is no return from MAIL FROM:
450 4.4.1 [internal] Connection Timed Out
5. When there is no return from RCPT TO:
450 4.4.1 [internal] Connection Timed Out
6. When there is no return from DATA:
450 4.4.1 [internal] Connection Timed Out
7. When there is no return from RESET:
450 4.4.1 [internal] Connection Timed Out
The timeouts for Email.cloud are as follows.
Client/Sender to ESS Service
Connect_Timeout = 240 sec / 4 min
EHLO_Timeout = 240 sec / 4 min
Mailfrom_Timeout = 240 sec / 4 min
Rcptto_Timeout = 240 sec / 4 min
Body_Timeout = 240 sec / 4 min
Rset_Timeout = 240 sec / 4 min
Idle_Timeout = 240 sec / 4 min
ESS Service to Client/Recipient
Connect_Timeout = 60 sec / 1 min
EHLO_Timeout = 300 sec / 5 min
Mailfrom_Timeout = 300 sec / 5 min
Rcptto_Timeout = 300 sec / 5 min
Body_Timeout = 600 sec / 10 min
Rset_Timeout = 300 sec / 5 min
Idle_Timeout = 5 sec