Hello,
This doesn't look like a MD5 password; the value slapd expects is something like
slappasswd -h '{md5}' -s testpw {MD5}ju4+/d4ets9mOaWISDYr9A==
it indead was a md5 hash generated by the perl-mdoule Crypt::PasswdMD5. I'm now generating it with Digest::MD5 -> md5_base64 and appending the missing "==". Authentication works now.
Regards Marten