ePolicy Orchestrator data source stops gathering events

Error log 

tail -f -n 50 /var/log/epo.24

Mar 11 14:19:25 L_ERROR 01906|ct_fetch returned* _FAIL at [collector/connector/mssql/ntds.c:209 (tds_exec_reader)]
Mar 11 14:19:25 L_ERROR 01906|tds_exec_reader failed at [collector/connector/mssql/tds_connector.c:194 (tds_connector_exec_query)]
Mar 11 14:19:25 L_ERROR 01906|exec_query failed at [collector/connector/connector.c:165 (connector_exec_query)]
Mar 11 14:19:25 L_ERROR 01906|Failed to execute query at [collector/client/client_wrapper.c:143 (client_wrapper_get_data)]
Mar 11 14:19:25 L_ERROR 01906|An error occurred, sleeping for 5 min(s), 00 sec(s) or 300s before retrying

epo SQL Connect test via GUI -> OK

The datasource works fine for a long time. now it stops working

any ideas?

ESM 10.3.4