Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding.
Description: An unhandled exception occurred during t
You can accomplish this by adding "Connect Timeout=90" to the connection string. If your query is taking longer than 30 seconds though you should really consider optimizing the query somehow. Indexes may need to be added or a view might need to be created, etc.
Edited to correct issue pointed out by @Stijn comments.