Connection PoolTimeOut Connection

Hi All,

We have a requirement of uploading 500 rows at a time. Out of 500 instances i see few instances are failing with the below error.

a!queryRecordType [line 2]: APNX-3-4300-001: Connection pool drained - too many concurrent requests: org.apache.http.conn.ConnectionPoolTimeoutException: Timeout waiting for connection from pool) (Data Outputs).

What could be the reason of failure though the data is being fetched from the cached data of a record type?

Thanks in Advance !!