I found part of the problem, and it was the zimbraProxyAllowedDomains setting in the COS. I compared the entries in the default COS to the entries in all my custom COSs, and discovered all my custom COSs were short about a dozen or so entries compared to the default COS.
I added all the missing entries and now the Yahoo! Local button works.
Code:
zmprov mc COS zimbraProxyAllowedDomains value1 zimbraProxyAllowedDomains value2 zimbraProxyAllowedDomains value3 etc.........
then
Code:
zmprov fc cos COSNAME
...on every mailbox server. Problem is all it brings up is a blank map page. Anyone know how to fix that?
Thanks,
Matt