NetWare 6.5 SP4

Cannot create Printer Profiles in iManager

When attempting to create a printer profile,
I get a dialog stating:
Printer authentication failed. Do you want to try again?

When answering "Yes", a login dialog for the iPrint proxy identity
is displayed (my proxy user is .iPrintproxy.skoler)
According to documentation, this user has no password,
but trying to login with the users identity in the dialog also fails.

Thereafter a new error message appears:
The SSL connection has been closed.
Error group: SSL
Error code: 6

At the same time, dstraceing ldap activity shows this
on the server screen:
LDAP: NDS login failed for proxy identity 'CN=iPrintproxy.O=Skoler',
err = no such value (-602)

LDAP: Could not configure proxy context in ReadConfigFromDS,
err = no such value (-602)

Applying a password on the proxy user does not help either.

I have the same problem in two different eDir trees.
PKIDIAG shows no errors.
DSREPAIR does not help.
All LDAP Server and Group objects are in place.
The proxy users are associated on the appropriate LDAP Group objects.
The iPrint server listens on port 389, 631 and 636.

Ideas anyone?
How can I get iPrint proxy to work?