I got this while trying to get my zcs5.0 to relay to another mta that requires authentication

warning: SASL authentication failure: GSSAPI Error: Miscellaneous failure (see text) (open(/tmp/krb5cc_51): No such file or directory)

(SASL authentication failed; cannot authenticate to server xxx generic failure)


I just added this to my main.cf and created the necessary password map file

smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/opt/zimbra/postfix/conf/smtp_password


the relay MTA is an Exchange supporting the following

250-TURN
250-SIZE 15728640
250-ETRN
250-PIPELINING
250-DSN
250-ENHANCEDSTATUSCODES
250-8bitmime
250-BINARYMIME
250-CHUNKING
250-VRFY
250-TLS
250-STARTTLS
250-X-EXPS GSSAPI NTLM LOGIN
250-X-EXPS=LOGIN
250-AUTH GSSAPI NTLM LOGIN
250-AUTH=LOGIN
250-X-LINK2STATE
250-XEXCH50
250 OK


Will appreciate any help. Thanks