Help solving a Clustering Issue: [sqsrvres] ODBC sqldriverconnect failed

I have a 2 node cluster (NODE-A & NODE-B) with 2 SQL instances spread between them. INST1 prefers NODE-A, INST2 prefers NODE-B. INST1 started generating errors then, failed over to NODE-B. Migrating INST1 back to NODE-A generates the connection errors after it logs a "Recovery is complete." message.

Win 2008 R2 Ent.

SQL 2008 R2 Ent.

Errors from the Event Log after first failure:

[sqsrvres] CheckQueryProcessorAlive: sqlexecdirect failed
[sqsrvres] printODBCError: sqlstate = HYT00; native error = 0; message = [Microsoft][SQL Server Native Client 10.0]Query timeout expired
[sqsrvres] OnlineThread: QP is not online.
[sqsrvres] printODBCError: sqlstate = 08S01; native error = 0; message = [Microsoft][SQL Server Native Client 10.0]The connection is no longer usable because the server failed to respond to a command cancellation for a previously executed statement in a timely manner. Possible causes include application deadlocks or the server being overloaded. Open a new connection and re-try the operation.
[sqsrvres] ODBC sqldriverconnect failed
[sqsrvres] checkODBCConnectError: sqlstate = HYT00; native error = 0; message = [Microsoft][SQL Server Native Client 10.0]Login timeout expired
[sqsrvres] checkODBCConnectError: sqlstate = 08001; native error = ffffffff; message = [Microsoft][SQL Server Native Client 10.0]A network-related or instance-specific error has occurred while establishing a connection to SQL Server. Server is not found or not accessible. Check if instance name is correct and if SQL Server is configured to allow remote connections. For more information see SQL Server Books Online.

Check SQL server configuration manager and see if the SQL browser is turned on. Check to see if dynamic ports are used or that 1433 is not being used by something else.

Also, try: sp_configure 'remote access' and let me know what is returned.

StackExchange Database Administrators Q#1214, answer score: 2