Tony of TP-Link helped me massively with a response 2019-01-04 15:54:35 to a member's major problem, "Archer C9 AC1900 won't connect to Modem." I had the same problem with a new Archer C9 AC1900. It was maddening - no WiFi service from an all but brand-new (only two weeks old), highly touted product and I considered eating a loss on the router by removing it and returning to Linksys products, which had served us flawlessly for 20 years.

I'd found Tony's superb fix with a last-chance Google search. My question today: Tony begins in 2019, "There are two things that usually cause this..". I successfully used the fix where he says, "First...", and wondered if the second fix was to be assumed by his language below the paragraph commence ing, "First...". 

If it were not, could Tony share what is the seconds thing? I would like to prepare for any potential additional router failure as it is so calamitous being without WiFi here, and the TP-Link router documentation is mediocre at best.

Thank you very much indeed for any consideration!