HELP!!! --- PIX 501 lossing connection with 1 side of the network

[accomp]

Hello, I have offices that are connected with VPN solution. I am using on office1 (Main Office) a VPN 3000 concentrator and on office2 I have PIX 501 that allows users to access to my main office.
My problems is that users on office2 are loosing connection to the office1 and they are not able to validate the password to the Domain server that is located in offcie1.
The only way to bring the connection back is by restarting the PIX 501.
Somebody have some idea why it happen, I will aprreciate all suggestions.
Greetings
ACCOMP

 

[baddos]

It may be running into it's connection limitation. Do a show conn count in the console.