@Mark_kg you can use a software controller on a pc. in my opinion it is better than a hardware controller. you can run the controller on a windows pc or linux, there are many who use raspberry pi for...

@Mark_kg You need Java, have you installed it? You can also try this prerelease version, it has Java built-in so you don't need to install it yourself....

@WiltecDavid Change your DNS to cloudflare

Ok, I think I fixed it, I ran a restore of the last good backup from 5.15.8.2, now restore works after backup of 5.15.20.11.. something has clearly bugged the controller on version 5.15.20.7 and up,...

@Vincent-TP I have a controller that I can't restore, I've tried on several devices with both windows and linux servers but it fails every time. It looks like all backups from 5.15.20.7 and up are...

@lkakas I don't have any more suggestions for you, so we'll probably have to wait for TP-Link.