I´ve coexistence of Exchange 2003 SP2 and Exchange 2010 SP3 servers.
Problem I´m facing
I have users using Outlook 2010. User "A" is located on Exchange 2003 server. User "B" is on Exchange 2010.
User "A" could not see Free/Busy of user "B" , but user "B" is able to see F/B of user "A".
Do you have idea? Thanks.
According to your description, the user in Exchange 2003 can see the free/busy information of Exchange 2010 users, but the reverse cannot.
Since users in Exchange 2003 can see the Free/Busy information of Exchange 2010, it seems the replication for public folder is fine.
Does the user in Exchange 2010 be able to see other Exchange 2010 users?
Please run Test E-mail AutoConfiguration and check the Autodiscover and EWS services.