'Unable to Process Request' error?

[Chris Ashley]

We have a web service which is giving the following error to one of our
clients:

"System.Web.Services.Protocols.SoapException: Server was unable to
process request. ---System.InvalidOperationException: Timeout expired.
The timeout period elapsed prior to obtaining a connection from the
pool. This may have occurred because all pooled connections were in use
and max pool size was reached.

at
System.Data.SqlClient.SqlConnectionPoolManager.GetPooledConnection(SqlConnectionString
options, Boolean& isInTransaction)

at System.Data.SqlClient.SqlConnection.Open()

at NHIWebApp.DataAccessLayer.DataConnection..ctor()

at NHIWebApp.WebServices.OrderDetails.GetBranches()
"

Is this being caused by our web service or by the client? It is strange
because I have tried the same code he is using here and also at home
and I cannot replicate the error. They are quite heavily locked down
and behind a proxy server so could this have something to do with it?

I just want to make sure that the problem does not lie with my web
service.

Regards,

Chris