Router can't logon to internet server

Hello, I have a micro pc working just as a pbx:

Kernel Version 2.6.32-220.17.1.el6.i686 (SMP) i686
Distro Name Icon CentOS release 6.3 (Final)

The problem is when for any reason the router is rebooted, the router cannot re-login to the internet isp. If I disconnect this micro pc (pbx server) from the network the router automatically connects to the isp without any problems. After the router is connected to the isp I can connect the micro pc to the network and all works fine.
Can anyone help me?

Regards,
Marcelo

It would be very helpful to know what model of router you are using and how you have configured it.

Thomson TG799vn and is is isp configured

I think it’s not the router because I had the sane problem with other router.

Please help me!

UP