have you change your dial up ID from @home.maxis to @public.maxis, (SOS)

as adviced by CHIP CN above, try check your windows firewall or antivirus firewall

sometime firewall will have issue, you can try disable your windows firewall and antivirus firewall temporary, then check and see if your port open, after testing do remember to enable your firewall back

is your apps that utilise the port is opened and running? if there is no app listening to the port, when you check the port using some website tool it will just say the port closed or not response from port.