Accessing an application through OAG gets ERR_TOO_MANY_REDIRECTS error in the browser. The issue does not happen when the application is accessed directly, without OAG.
 

Browser developer tools does not show "x-oag-host" header OR OAG session cookie "SessionCookieHFL16428SINFE71QMY4V" value getting changed. It shows that a valid OAG session persists on one single node. 
 

• Okta Access Gateway

This issue can happen in case of the following scenarios:

• The protected web resource for the configured application is not using the correct protocol. That means the backend web application was configured to use https whereas in OAG protected web resource it was configured with http. Because of that whenever backend receives a request on http, it redirects to https resulting in a loop and eventually ERR_TOO_MANY_REDIRECTS . 
• When both public & protected web resource are same and both resolves to OAG appliance IP.  
• In case of network/resolution issues
   

• Make sure the protected web resource is the exact URL that is used to access the application directly. 
• Make sure the host resolution is correct using DNS lookup.
• Make sure Curl tests from the OAG appliance is receiving the same response from backend as when it is tried directly from the client machine.  

Related References

• DNS Lookup
• Connectivity test (cURL) ​​​​​​​