I cannot connect to server when I use my wireless network

Hi there,
I have a strange problem:
I am not able to connect to the server when I am using my wireless network at home. Even if I use a cable to connect from the Ethernet port of my wireless router I'm still unsuccessful.
However, when I try to connect with the cable coming directly from the provider I am able to connect.
I think there is something wrong with my wireless router.
I should mention that I could connect to the sever with my wireless router 2 weeks ago but since then I don't know why it is not possible anymore.
any help, suggestion, or guidance would be highly appreciated.
Thank you for reading
Abbas