DNS Sync API Issue

I'm getting two errors, anyone seen these before (I searched and didn't see anything), also enabled debugging and the error message doesn't change. These happen when trying to add a server to dns sync. I've got 3 dns servers, all setup exactly the same....this is happening with 2 of them, the other one synced just fine.

» API failure : Invalid return payload: enable debugging to examine incoming payload (XML error: Invalid character at line 11)

» API failure : Invalid return payload: enable debugging to examine incoming payload (XML error: Invalid document end at line 2)