SUMMARY
Email relay server reports Insufficient system resources
ISSUE
Emails are not being received.
To determine if this is a result of "Insufficient system resources", run the following test.
- Login to the Unitrends Backup systems console or use putty to access a command line.
- Run a telnet to the mail server using port 25 (or the port being used for email relay).
[root@UB ~]# telnet 10.10.10.10 25 //where 10.10.10.10 is the IP of the mail server and port 25 is being used for email relay
Example output below (last line is important):
Trying 10.10.10.10... Connected to 10.10.10.10. Escape character is '^]'. 220 DCExchange.domain.local Microsoft ESMTP MAIL Service ready at Wed, 12 Apr 2017 19:19:59 -0500 EHLO 250-DCExchange.domain.local Hello [10.10.10.11] 250-SIZE 37748736 250-PIPELINING 250-DSN 250-ENHANCEDSTATUSCODES 250-STARTTLS 250-X-ANONYMOUSTLS 250-AUTH NTLM 250-X-EXPS GSSAPI NTLM 250-8BITMIME 250-BINARYMIME 250-CHUNKING 250 XRDST MAIL FROM:root@UB.localdomain 250 2.1.0 Sender OK RCPT TO:user@domain.com 550 5.7.54 SMTP; Unable to relay recipient in non-accepted domain RCPT TO: user2@domain.com 250 2.1.5 Recipient OK DATA 354 Start mail input; end with <CRLF>.<CRLF> THIS IS A TEST EMAIL FROM UNITRENDS . 452 4.3.1 Insufficient system resources
- Search the maillog on the Unitrends Backup system for the key phrase "Insufficient system resources".
# grep "Insufficient system resources" /var/log/maillog* Apr 12 08:38:37 UB sendmail[16715]: v38E04xl029431: to=<user@domain.com>, ctladdr=<root@UB.domain.local> (0/0), delay=3+23:38:33, xdelay=00:00:00, mailer=relay, pri=8764371, relay=[10.10.10.10] [10.10.10.10], dsn=4.0.0, stat=Deferred: 452 4.3.1 Insufficient system resources
RESOLUTION
Check the mail server to determine if it has adequate system resources such as storage space, memory and processing threads. This may also be caused by an improperly running or rouge service on the mail server.
Alternatively, an alternate mail server should be used to further determine the cause of this error.
CAUSE
The mail relay process "sendmail" receives this output from the mail server.