Error opening Calendar after transferring Server on new hardware

Hi all,

At beginning wie have two Partitioned Server / 2 NotesDomains on a 32Bit-Windows

(Domino Release 8.5.2FP3 HF65). Opening the Calender in the other domains works fine.

Now we transfer one server on a new hardware

(Windows2008R2, 64Bit) and Upgrade the Domino Server to Release 8.5.3FP3)

No configuration changed. IP’s from the Instance are switched.

After that: If Users try to open the calender

in the domain which still resides on the 32-Bit-Server they received the error: Calendar for person xxxx could not be opened.

I’ve tried clients from Release 8.5.3FP2 'til Release 9. Same Error.

Somebody got that issue ?