Entries are not created in the Zimbra diary, was it?

Question

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Available - Zimbra Opensource 8.5 on Ubuntu Server 12.04
Problem - When I try to create an appointment in the diary, I get a message that the appointment has been created, but the list is still empty, the appointment is not created and is not displayed anywhere.
Faced with this? I have this problem on multiple servers.
UPD: works under chrome and donkey. Doesn't work under firefox. This is not the first time I have encountered incomprehensible behavior of Zimbra under firefox. very strange