ERR_TOO_MANY_REDIRECTS – Website redirects endlessly

Saved website data or incorrect server configuration are often involved.

Do not factory-reset a router speculatively or indiscriminately disable Wi-Fi security or a firewall. Get permission before changing someone else’s network.

Test the address in a private browser window without logging into unknown sites.
If it works there, just delete cookies and website data from this site via the browser settings. This will log you out there.
If the error persists on other devices, contact the provider; no Windows repair necessary.

Test after each step and stop when the issue is solved. Checkmarks are not permanently saved.