Server Too Busy, Retry Later, SMTP and POP rejects connections...

Hello

I use a QNAP TS119 with Xdove 1.333 installed.
I have Xmail server: 1.25
and PHPXMail 1.5 for the administration.

Since few weeks I have problems.

When I telnet SMTP port I got :

So no new emails can come in

I have to restart Xmail to get a normal use...

When the problem occurs :
POP access is also unavailable (-ERR Server too busy, retry, retry later)
and posting with the Webmail fails (SMTP can't be reached)

This is what I can tell :
- I have no CPU problems... less than 10 % used
- No bandwith problem
- Netstat show only 10 SMTP connections...
- The problem is the same on the LAN and the WAN

What I did :
- Disabled CustMapsList
- Restart the server every hours...
- I disabled POP on my router

Now It works... but I don't think that restarting the server every hours is the good choice...

I've searched on the internet but did not find a similar problem.

Can someone help me?

PS: Thanks for the activation Harald

UP