I'm experiencing trouble with OpenID sign-in on site.
What are the needful steps that can help on troubleshooting OpenID login issues?
Based on our experience, these steps can help troubleshooting OpenID login issues.
Are you behind a proxy or firewall? OpenID requires very long URLs and proxies / firewalls with aggressive settings will sometimes block OpenID accidentally. This has been documented a bunch of times, often in corporate settings. If so, try without the proxy/firewall -- or convince your network admins that OpenID is in fact safe to allow..
Have you tried clearing your domain cookies? Sometimes the cookie information gets corrupted somehow (not quite sure what happens here) but clearing cookies for the domain in question (serverfault.com, superuser.com, stackoverflow.com) has been known to work.
Have you tried in a different browser? The world is lousy with great browsers, and switching out browsers can quickly tell you if there's something "wonky" with your browser plugins, configuration, etc.
Does your OpenID profile have invalid information in it? This is quite rare, but we have seen instances where profiles with problematic info (like invalid / gibberish email addresses) cause exceptions on our end. If possible, try a new, default OpenID or switch OpenID providers just for testing.
Is your site especially slow to respond? In order to prevent denial of service attacks, it's common for OpenID libraries to have cutoff times of a few seconds when making HTTP requests. If you're delegating, try putting your delegation on a blank, plain vanilla HTML "hello world" page to remove any processing delays.
Do you use a self-signed SSL certificate? Because self-signed SSL certificates, if generally accepted, would allow DNS poisoning or other network attacks to enable identity spoofing, we do not support them.
Is your HTML valid? If you are OpenID delegation, something as simple as a missing opening
<head> tag will cause an OpenID login failure but you won't necessarily know it from viewing your site in a modern browser. Check your HTML for validity.
There's also a diagnostic page which might give you more information about any potential problems:
After using the above page, check the "recent logs" link to see what is going wrong.
Don't wait until after something goes wrong to set up an alternate OpenID in your profile.