If an application is created with a public URL that lacks a subdomain, saving it will fail with a Server Side Error message in the UI and the following error in the logs:

message:Failed generating cookieDomain, developerMessage:Check that valid relaydomain is being used

The full error message is similar to:

2025-05-29T15:45:42.000-04:00 oag-admin.domain.tld ACCESS_GATEWAY WEB_CONSOLE handling service exception: com.icsynergy.spgateway.service.NotFoundException Error: com.icsynergy.spgateway.domain.SPGWError(type:NotFoundException, status:0, code:SPGW_NOT_FOUND, message:Failed generating cookieDomain, developerMessage:Check that valid relaydomain is being used, errors:[:], context:null)

• Okta Access Gateway (OAG)

The application's public URL must have a subdomain, which must be in FQDN format. 

• For example, "companyapp.com" is an invalid public URL, but "app.company.com" is valid (where "app" is the subdomain). 

Modify the application's public URL to include a subdomain and save the app again.

NOTE: "www" can technically be used as a subdomain, but this is generally not recommended because users will need to include this in the URL when accessing the application. Otherwise, OAG will return an Unknown host 400 status code error page.