Can't launch Unity 3.5.7

We are long time users of 3.5.7, on which we built a commercial project that we have to maintain.

We could launch the editor until 2 weeks ago.

Now we get an error message "The internet activation server returned a server error (HTTP status 503).

Press OK to manyually activate your software.
ID : ePAY : 16005 / WPSW : 767
"

Manual activation doesn’t work.

I have been in touch with support who gave us ports to open but still nothing.

Tried to launch as admin, with compatibility mode…

We are stuck.

Any ideas ?

I also have exactly the same issue and no solution. Unity 3 is not supported anymore but we need to maintain an existing large commercial project.

Could you try the automatic activation again? We restarted the 3.x license server.

Thank you Superpig !
This is a miracle.
Please keep the server working…
Take care