I realise this could be seen as a duplicate but I've skimmd through the top dozen results and can't find anything comparable.
I've run my own (very simple) OpenID server at christopher.woods.name for quite a few years, mostly using it with SO sites; initially I signed up and used my email address to authenticate, later adding my OpenID.
Around December last year, I started to get this dreaded "message signature was incorrect" error - I've tried on several machines in various browsers and on various connections and get the same result every time.
If I open any SO page on the one machine which still has a session cookie saved (I think from when I logged in with my associated email address), I get the usual "you've been logged in - click here to refresh" banner, and I can comment as usual.
What's causing this? I've changed nothing with my OpenID endpoint (it's really very, very simple, not even backed with a database as it's just me using it) — so I can only assume something on the SO side must have changed.
Grateful for all help or suggestions...