We recently created a custom appointment form and set it as the default form for a resource. Users can click on the resource, click new appointment, and fill out a custom form. Everything worked great. We added some other resources, set rights for the new resources and published the form. at some point, the organizer field is now blank. When users receive a request to attend a meeting, you get a "You cannot respond to a meeting without an organizer. you must add an organizer field to the item". I looked at the custom form, and organizer is greyed out, so I can't force a solution.
I've been searching and reading about this issue at a lot of sites. Apparently it's a common issue. Lots of suggestions but none that seemed to point to a solution.
We have Exchange 2010, approximately 150 users, and a variety of outlook versions mostly 2010 and 2007. Our users are not on a domain, and mostly remote, using HTTP/RPC for their outl