Have you tried to use another SIM card in the router and do you have the same issue? If the SIM card is working fine on the phone, the issue should be the MR200, contact retailer or TP-Link about...

Usually QOS function will just limit the speed instead of block data, is the Foronius Solar system using the APP or website? If you wait for a long time, can you see the page load?

Hi, Set up the D7 as a access point will be more suitable in your case. Then you can use the wifi from the TD-W8968 and Archer D7. Change the D7's LAN IP address to the same subnet with the 8968,...

If the Deco still working when the light turns to red, you can try to change the DNS server to 8.8.8.8 and 8.8.4.4, may it help.

Yes is port 80.

press the pair button on the adapters for 15 seconds then repair them, it may help..