Connection timeout with certain DBs

I am getting a connection timeout error when connecting to a DB I want to search.  Other DBs on the same server seem fine, and the same DB on another server (QA and Dev servers) is also not working.  Below is the log...

17 May 2018 09:55:12.316 [Redgate.Usage.AsynchronousUsageApiClient] INFO  RedGate.SQLSearch.UsageReporting.ApplicationUsageHelper - Usage reporting request made to https://productusage.red-gate.com/v1/usageevents
  Number of submitted usage events = 1
  HTTP status code = 204 NoContent
  Response body =
17 May 2018 09:55:16.821 [16] INFO  DatabaseObjectStorage - Inserting job steps into index
17 May 2018 09:55:16.824 [26] INFO  DatabaseObjectStorage - Inserting objects into index
17 May 2018 09:55:17.190 [16] INFO  DatabaseObjectStorage - Done
17 May 2018 09:55:17.196 [16] INFO  DatabaseObjectStorage - Inserting jobs into index
17 May 2018 09:55:17.335 [16] INFO  DatabaseObjectStorage - Done
17 May 2018 09:55:52.559 [26] ERROR DatabaseObjectIndexer - Exception while indexing database ConstructionCost:
System.Data.SqlClient.SqlException (0x80131904): Timeout expired.  The timeout period elapsed prior to completion of the operation or the server is not responding. ---> System.ComponentModel.Win32Exception (0x80004005): The wait operation timed out
   at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)
   at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose)
   at System.Data.SqlClient.TdsParserStateObject.ReadSniError(TdsParserStateObject stateObj, UInt32 error)
   at System.Data.SqlClient.TdsParserStateObject.ReadSniSyncOverAsync()
   at System.Data.SqlClient.TdsParserStateObject.TryReadNetworkPacket()
   at System.Data.SqlClient.TdsParserStateObject.TryPrepareBuffer()
   at System.Data.SqlClient.TdsParserStateObject.TryReadUInt32(UInt32& value)
   at System.Data.SqlClient.TdsParserStateObject.TryReadPlpLength(Boolean returnPlpNullIfNull, UInt64& lengthLeft)
   at System.Data.SqlClient.TdsParser.TryReadPlpUnicodeChars(Char[]& buff, Int32 offst, Int32 len, TdsParserStateObject stateObj, Int32& totalCharsRead)
   at System.Data.SqlClient.TdsParser.TryReadSqlStringValue(SqlBuffer value, Byte type, Int32 length, Encoding encoding, Boolean isPlp, TdsParserStateObject stateObj)
   at System.Data.SqlClient.TdsParser.TryReadSqlValue(SqlBuffer value, SqlMetaDataPriv md, Int32 length, TdsParserStateObject stateObj, SqlCommandColumnEncryptionSetting columnEncryptionOverride, String columnName)
   at System.Data.SqlClient.SqlDataReader.TryReadColumnInternal(Int32 i, Boolean readHeaderOnly)
   at System.Data.SqlClient.SqlDataReader.TryReadColumn(Int32 i, Boolean setTimeout, Boolean allowPartiallyReadColumn)
   at System.Data.SqlClient.SqlDataReader.GetValueInternal(Int32 i)
   at System.Data.SqlClient.SqlDataReader.GetValue(Int32 i)
   at System.Data.SqlClient.SqlDataReader.get_Item(Int32 i)
   at RedGate.SQLSearch.Indexing.SQLServer.SqlServerConnection.<ExecuteQuery>d__2.MoveNext()
   at RedGate.SQLSearch.Indexing.SQLServer.SqlDatabaseReader.<GetObjectsFromSysobjectsQuery>d__8.MoveNext()
   at RedGate.SQLSearch.Indexing.SQLite.DatabaseObjectStorage.InsertObjects(IEnumerable`1 )
   at RedGate.SQLSearch.Indexing.DatabaseObjectIndexer.Index(ISqlDatabaseReader , IDatabaseObjectStorage )
   at RedGate.SQLSearch.Indexing.DatabaseObjectIndexer.Index()
ClientConnectionId:838e1aa3-2c20-4e2b-a770-d0a9be4dea1a
Error Number:-2,State:0,Class:11