I’ve been consistently having this problem since the release of the Patch Update for Season 22. I’ve done every troubleshooting step possible, including winMTR testing and a variety of other things (disable ipv6, dump dns, refreshing ip, disabling / re-enabling firewall bypass for BNet and D3) and much more. I even changed my password and released / renewed my authenticator…I don’t know what else to do and so far, the only blue posts I’ve seen were just to tell people to run winMTR test and post their results and not once have I seen a blue response to anyone’s test results that were posted. After doing some research, I’ve calculated from all of the threads dating back to 10/06/2020 (just shy of 2 months ago) there’s been a total of 378 individual players in the US struggling with this problem, and 293 that I was able to find on the EU forums, that have had this same issue. Just since the drop of S22 Patch, there’s been around 290 US cases of Error 45 and Error 1016 (both generic disconnect errors) from what I’ve gathered.
I have no clue what else to do, and I am fed up with the toxic community in WoW (not to mention Shadowlands sucks) so…Diablo 3 with the addition of the 4th cube slot has truly been my biggest interest during this quarantine fiasco. I am hoping that Blizzard pulls through and starts taking this issue seriously, because I’m quite certain that a lack of resolution for this matter and further sweeping it under the rug as it seems they’ve been doing, will lead to a huge loss of player-base. A few times that I have managed to get into the game and linger around in menus or do some rifts, I’ve hit up general chat and asked about Error 1016 and Error 45 and at least 30 people flooded me with private messages and in Gen chat, responding to this problem asking if I’ve found a solution or gotten any type of information from Blizzard in regards to a troubleshoot or an investigation pending with the matter at hand. Again as I said, NO RESPONSE from Blizzard whatsoever…I’m going to open a ticket immediately after typing this 
Please feel free to add me to your friends list @ Conjuring#11624 I would love to keep in touch with you, in hopes that one of the two of us finds a permanent solution outside of uninstalling the game and never looking back! ROFL!!!
#WishingYouLuckMyFriend