https://answers.microsoft.com/en-us/surface/forum/all/surface-3-not-connecting-to-wi-fi-6/1cd1d8d8-c...   this fixed my problem.   my random thoughts: It looks like for some reason Microsoft Windows and / or Microsoft Surface (yes they make both software and hardware for this!) stopped automatically updating the Marvell network drivers at some point. The SP3 probably had no idea how to communicate with the TPG modern until one installs the most recent (still old) drivers. Also something odd about the Sagemcom that makes it not backward compatible with older devices?? Curious but also seriously I don't really care lol ... View more

https://answers.microsoft.com/en-us/surface/forum/all/surface-3-not-connecting-to-wi-fi-6/1cd1d8d8-c252-418c-a4ee-3846e526720d   this fixed my problem. sadly I bought a new laptop before I found this solution. sp3 was kinda old and slow. ... View more

Was this ever resolved?   I have this same wi-fi issue with an old Microsoft Surface Pro 3 (SP3) to a Sagecomm 5G 5866T. The SP3 has connected to literally hundreds of different networks in it's life without issue until now! ... View more