Dear NTLMAPS team,
After spending some time I figured out a problem caused by using http://proxyaddress instead of proxyaddress for PARENT_PROXY in the server.cfg file.
The debugging file shows the following when using http:// prefix:
*** Connecting to remote server...(http:8080)...Failed.
*** Finishing procedure started.
*** Closing thread...Done.
Which then was fixed when proxyaddress is used without a prefix.
*** Connecting to remote server...(172.x.x.x:8080)...Done.
*** Sending client request header to remote server...Done.
OS used: Windows XP Proffessional SP2
NTLMAPS v. 0.9.9.6