Google SSO and EzProxy: Error 400: redirect_uri_mismatch

Solution for Google SSO and EzProxy: Error 400: redirect_uri_mismatch
is Given Below:

Anyone have any advise on the best way to handle this type of scenario?

-Access to our online product is based on IP address authentication.

-We whitelist the IP address of a university’s proxy server.

-User gains access to our website through their university’s proxy server.

-The proxy server rewrites the URL from to

-Within our site, we have a separate module that a user can log into for a personized experience. We set up Google SSO so the user can log into this module with their google account.

-When trying to log into this separate module via google, the Proxy user gets Error 400: redirect_uri_mismatch

-We add as an authorized redirect URI, and a Javascript origin in google cloud platform, that resolves this university’s particular issue, but…

We have 500 different proxy servers accessing our site, is there a way to accommodate them all without adding 500 different javascript origins and redirect URIs? Is there a way to bypass the proxy altogether?