The following error is being logged:
"![2009/03/23 05:31:22.541] (3) Error :<F/B Sender> (39273) Failed to collect Free/Busy: Code : 0x80070057,Description : The parameter is incorrect."
Possible cause - publication is disabled or configuration problem.
Please examine all publications in HQ and in branches (on publisher's side) and determine which publication is not intended to be disabled. Once it is re-enabled the error should disappear.
If the error is not due to a disabled publication upgrade to version 3.7 or greater to resolve this issue.