Mails to remote recipients stuck in queue, please help.

[PremF]

I'm using Plesk 9.3.0 with Qmail on Redhat el5.
By now, all mails to remote recipients which are sent from my server stuck in queue (local mail sending/receiving is fine).

I see many lines of this error in maillog:
deferral: Sorry,_I_wasn't_able_to_establish_an_SMTP_connection._(#4.4.1)/

Port 25 of my server is working fine. So I'm quite confuse about the cause of that error.

How should I do to solve this? Please suggest.

 

[IgorG]

Look at http://kb.odin.com/en/1398

 

[NickolayB]

I'm using Plesk 9.3.0 with Qmail on Redhat el5.
By now, all mails to remote recipients which are sent from my server stuck in queue (local mail sending/receiving is fine).

I see many lines of this error in maillog:
deferral: Sorry,_I_wasn't_able_to_establish_an_SMTP_connection._(#4.4.1)/

Port 25 of my server is working fine. So I'm quite confuse about the cause of that error.

How should I do to solve this? Please suggest.

I have a same problem.
How do you solve this ?