Got it to work by distributing it to test flight and then pressing the distribute button again, but then choosing App Store. Xcode version 26 RC (17A321) macOS 15.6.1

I have been trying all morning with Xcode version 26.0 (17A321), on macOS 15.6.1 (24G90). And I'm having the same issue.

Same. I get "Unsupported SDK or Xcode version." using Version 26.0 (17A321).