Hi,
Already opened up a case to symantec.
We had a LDAP Synchronization enabled (( ControlCenter pushes AD userdb to the scanners on the DMZ) with DHA enabled. After the upgrade the scanner itself tried connecting directly against our LDAP server which obviously didnt have the proper firewall openings between Scanner<->LDAP. That resolved in big delivery problems with an error saying "421 Unable to process message at this time". You can read about it here:
http://service1.symantec.com/support/ent-gate.nsf/854fa02b4f5013678825731a007d06af/2ce500484e39fc7c802576e4002f8d03?OpenDocument
It didnt help to disable/delete the LDAP Sync from the ControlCenter. Recreated the LDAP sync - No go - Still the same problem. There is a command called "clear syncdata" and delete ddsdata which i tried too but it still tried to connect against the LDAP.
Our workaround was to open up TCP/389 in the firewall against our LDAP. When our delivery queue was empty we stopped/paused the mail delivery and we reinstalled the scanner with an OS-restore 8.3-11 CD and reconfigured the IP-Configuration. When the install was done, i deleted the scanner host from Administration>Configuration and then i added the scanner again. Everything was back to normal.
Today i upgraded our restored Scanner again to 9.0 and everything is looking OK so far...
BR