Which version of windows are you operating on?
Have you tried connecting the router directly to your computer?
If the issue still occur, I suggest you to try using a different platform, use the same internet connection and check if it's still unavailable for you. If that's the case, contact your ISP. If that's not the case, I suggest re-installing your entire OS to Windows 10 to get rid of any problems, since Microsoft is not developing anything below 10 any further and therefore has millions of bugs; especially with SA:MP.
Have you tried connecting the router directly to your computer?
If the issue still occur, I suggest you to try using a different platform, use the same internet connection and check if it's still unavailable for you. If that's the case, contact your ISP. If that's not the case, I suggest re-installing your entire OS to Windows 10 to get rid of any problems, since Microsoft is not developing anything below 10 any further and therefore has millions of bugs; especially with SA:MP.