I met the same problem today. My Mac system is Big Sur 11.4 and my iOS version is 14.6. Without the NAT64 option the network works well.

I'm having the same issue on M1 processor mac. This is really a pretty basic function that should work.

Does anybody find any workaround or fix? Same here. It's frustrating the connect backend always has strange bugs.

the PATCH request to save the change is returning 409, which indicates a parameter error but I compared the json it sends, no error found. No idea what's going on.