As first reported by 9to5Mac, it appears that Apple has temporarily removed the first beta of watchOS 5, less than 24 hours after it was first released following Monday’s WWDC keynote. While Apple doesn’t elaborate on specific reason for doing so, the note on the developer download page suggests that it was probably related to a problem that some users encountered while updating to the newest beta, which seems to be borne out by several developers who have reported problems ranging from getting Apple Watch to finish the beta update to actually ending up with a red exclamation mark and instructions to contact Apple support.
Seed 1 of watchOS 5 is temporarily unavailable. We are investigating an issue that may occur while updating. If you’ve experienced any issues, please contact AppleCare.
The configuration profile used to provision the Apple Watch for over-the-air updates to watchOS 5 betas has been pulled from the Apple Developer website, and the actual over-the-air update has also apparently been removed from the queue, so that even users who have already installed the profile won’t see the beta update until Apple decides to either make it available again or release an updated version.