I'm back, once again having problems with iPrint, this time authentication errors in Windows XP. I have set my printers to use Secure printing, medium security level. All of a sudden, I can't authenticate to printers from Windows XP. Windows 7 machines have no problem.

When I do a trace, I'm getting a lot of errors of this kind:

[00000A5C : 281343ms][NIPPLIB] - GetSessionLoginData - RegOpenKeyEx failed 2
[NIPPLIB] - The system cannot find the file specified.

[00000A5C : 285656ms][NIPPLIB] - GetUserLoginData - RegQueryValueEx failed 2
[NIPPLIB] - The system cannot find the file specified.

[00000A5C : 289109ms][NIPPLIB] - DeleteSessionLoginData - RegOpenKeyEx failed 2
[NIPPLIB] - The system cannot find the file specified.

[00000A5C : 285859ms][NIPPLIB] - HTTPDoRecv(TLS CONNECTION) - SSL_read failed to recv (error=5) - authentication was attempted
[NIPPLIB] - HTTP - The server terminated the connection because the keepalive timeout was reached and a request was not issued.

[00000A5C : 289109ms][NIPPLIB] - HTTPReadResponseHeader - bad HTTP status (401)
[NIPPLIB] - HTTP 401 - Unauthorized.

Since authentication is failing, it is the last two that look especially suspicious to me.

I can post more detailed traces if needed.