We are excited to announce that we have launched our new Hive Community! HiveNation will remain as an archive, but all new posts, discussions, and articles will be created on Hive Community. You can visit our new community at thehivecommunity.aerohive.com
First consider updating to HiveManager 6.6r3 if you haven't done so already, if it then continues to not work, open a support case with your point of support. I suspect that you will need to open a case. The error message to me suggests a backend issue.