You are suggested to contact VoIP provider to check the line first. By the way, you can ask for some suggestions from the support and make some changes on the router.

The function only works with mail account using port 25. Gmail is not. Not sure about the yahoo one.

I'm afraid not. Normally we can save the config file as a backup. But the config file of WDR4300 will cause some problem if you upload it after upgrade, which has been reported by many users on this...

Maybe it is DLNA compatibility issue.

Not all 11n devices support both 2.4GHz and 5GHz. Contact Samsung to confirm if the wireless card in your smart TV support dual bands or not.

Reset the swtich SG108E to factory defaults first. Use a computer or some other client to replace the mediabox and test if the problem continues. If SG108E works fine with other clients except the...