SQL exception: The query processor could not start the necessary thread resources for parallel query execution

We keep seeing this exceptions throughout the day on the main TeamCity page on TeamCity 8.0.4 - this used to be not a problem we ever saw on TC 7.

We use an external SQL database housed on a fairly high powered DB server - this should not be the issue.

Today this for the first time failed a build when a step refused to start.

Unexpected  exception SQLServerException: SQL error when doing: Fetching query  results SQL query: select bs.id, bs.branch_name from build_state bs join history  h on bs.id = h.build_state_id where bs.modification_id <= ? and        bs.build_id < ? and       bs.build_type_id = ? and       bs.id  <> ? and       bs.is_changes_detached = 0 and       bs.is_deleted =  0 and       (  h.status <= ? and          h.status <> 0)   order by bs.modification_id desc, bs.build_id desc SQL exception: The query processor could not start the necessary thread  resources for parallel query execution.


Is there anything we can do to address this?