Dylan discovered this when testing a community issue: https://forum.mattermost.org/t/mattermost-ios-app-1-8-0-saml-w-adfs-clicking-login-with-saml-button-displays-white-screen/5010
Reproduced on https://ci-linux-postgres.mattermost.com.
Only an issue on RN, doesn't repro on webapp or desktop app.
1. Set up Mattermost with SAML using ADFS (e.g. on https://ci-linux-postgres.mattermost.com).
2. Start the app (iOS / Android).
3. Choose login method as: With SAML.
Login works, no blank screen or errors.
Logging in via SAML or via email & password with ADFS causes white screen. Refresh symbol runs permanently.
On other servers, SAML using OneLogin and OKTA do not reproduce the issue.
Sometimes the screen does not stay blank but shows an error (see attached screenshot).