The NG-R2504P will not allow you to forward enough ports, to run World of Warcraft Downloader. You should try using the DMZ portion of this router if it is available. Alternatively you can try switching the router to bridged mode. You will need to contact your ISP to switch to bridged mode, so they can make the required changed on their end.
To test if your port has been properly forwarded, you can use our Port Checker tool.
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