The official unifi support Twitter account pointed to a solution it provided to another user, which was to use Google’s Public DNS. That said, there are other users who are still having connectivity problems on and off. Some of them were also already using the Google Public DNS before this issue began. There are a few among them who also tried Cloudflare’s public DNS, to no avail. And on the flip side, there are other accounts of the issue being resolved, with no action being taken.

— help me unifi (@helpmeunifi) February 17, 2020 I tested this myself earlier in the day, and my PS4 had no issues with connectivity. For what it’s worth, I’ve set my PS4 and router to use Google Public DNS the moment I got them. It’s uncertain if those who are still facing issues after switching to Google’s DNS only made the change on their PS4, on their router, or both. If you’re having connectivity issues with your PlayStation 4, you try using the Google Public DNS or Cloudflare public DNS. The steps to do so on your PS4 are in the tweet above. For your router, the steps will vary depending on the model you use. Google’s DNS server addresses are 8.8.8.8  and 8.8.4.4, while Cloudflare’s are 1.1.1.1 and 1.0.0.1. The entire situation sound similar to what happened between unifi subscribers and Ubisoft servers last week. The ISP claims issue has been resolved, but it looks like there are still users who are facing issues getting a connection. (Source: Unifi / Twitter)