@Salted11 

Hey, I am setting up my unraid server following spaceinvaderone's videos and ran into the same problem. Did you ever figure out a solution to this? Any help would be appreciated!!!

@pjb1988 Unfortunately no.  I did get a response from tech support, but it was rather rudimentary (put in Google DNS).  I've asked this same question on other forums as well, and haven't gotten a reply.  I wonder if this is a tplink router issue, in that this obstruction is "baked into" the functionality of the router.  That, or I don't have a good enough understanding of how this stuff works!  (Hopefully the latter).  Best of luck, and if you find a solution, I'll be grateful.

@Salted11 @pjb1988 hi both. I had the same problem and I was able to successfully provision by setting my Unraid DNS to 1.1.1.1 and 8.8.8.8 and then change the Deco DNS to the same. 

The DNS may not resolve immediately, it took a couple of minutes for me and then I was able to successfully provision.

Hope this helps.

@opusdeath 

Thanks for the reply. I actually just attempted to do the same thing that didn't work again after posting this and it worked fine. Not sure why it worked one time and why it didn't the first time.