Certain web apps or websites deployed behind OAG that use WordPress may give the below error in Safari for web, iOS, or iPadOS. The application still works when using other browsers like Chrome or Firefox:
 

cannot parse response (NSURLErrorDomain: -1017)
 

• SAML
• Okta Access Gateway
• Safari
• Okta Classic Engine
• A protected URL leads to a website or app that was created using WordPress.

This has been documented on the WordPress website, and the solution is to apply a custom Nginx directive:

• Go to the application Policies screen in the OAG Admin UI.

• Under the root URI (/), expand Advanced and add this line proxy_hide_header Upgrade.