@Brokker 

For tp-link router, I remember need choose interface in virtual server function, if you choose WAN1, you only are able to access internal server via WAN1.

As you said, you  have built two virtual server entries?

@TPTHZ 

This is my config. When only WAN1 linked up there is no problem. When links up WAN2 this config don't works.

@Brokker 

 You have many different servers in your LAN,  

       Every server all cannot work when you use WAN2?

       I have doubt about you testing method, you said when you enable WAN2, you cannot access the server.

      In this situation, which destinaton IP address  you are using? IP address of WAN1 or IP address of WAN2?

      Did you configure load balance function in this router?

      If you have configured load balance function, you need tick "Enable Application Optimized Routing"

      You can use telnet command to test if the specific port has opened, for example.

      You can type  telnet  ip address of  WAN1  57772,  test if the 57772 be opened.

      You can disable WAN1 port also, to test if there are something wrong with you WAN2 Line.

@TPTHZ 

I hate electronics and computers.

Now, unrasonability works.

Thanks a lot for your help.

Wish you a wonderfull year!!