expo build:ios Request failed with status code 504

I’m trying to build:ios on 2 projects and both are failing with the message:

Unable to find an existing Expo CLI instance for this directory, starting a new one…
Starting Metro Bundler on port 19001.
Tunnel ready.
Publishing to channel ‘default’…
Building iOS bundle
Finished building JavaScript bundle in 72511ms.
Building Android bundle
Finished building JavaScript bundle in 76072ms.
Analyzing assets
Finished building JavaScript bundle in 2160ms.
Finished building JavaScript bundle in 1938ms.
Uploading assets
› Closing Expo server
› Stopping Metro bundler
Request failed with status code 504
Set EXPO_DEBUG=true in your env to view the stack trace.

% expo diagnostics

Expo CLI 3.11.9 environment info:
System:
OS: macOS 10.15.2
Shell: 5.7.1 - /bin/zsh
Binaries:
Node: 12.12.0 - /usr/local/bin/node
Yarn: 1.21.1 - /usr/local/bin/yarn
npm: 6.13.7 - /usr/local/bin/npm
Watchman: 4.9.0 - /usr/local/bin/watchman
IDEs:
Android Studio: 3.3 AI-182.5107.16.33.5314842
Xcode: 11.3.1/11C504 - /usr/bin/xcodebuild
npmGlobalPackages:
expo-cli: 3.11.9