An error can occur if there is a shortage of CICS receive sessions.
Intermittent ECI_ERR_RESOURCE_SHORTAGE messages when sending an ECI request to CICS.
There are not enough receive sessions in the sessions definition.
Increase the RECEIVECOUNT value on the SESSIONS resource definition on the CICS® server to a value substantially greater than is theoretically necessary. Do this by setting RECEIVECOUNT to a value greater than the LOGONLIM value. For more information, see CICS server sessions definition.