Details
For performance and reliability reasons, these data sources should not be used with MID Server clusters:
-LDAP
-Export sets
-JDBC data sources
These external data sources should only be used with dedicated MID Servers.
For further information , i would like to ask you to check below documentation.
https://docs.servicenow.com/bundle/london-servicenow-platform/page/product/mid-server/reference/mid-server-clusters.html
Additional Information
There is no workaround for this limitation.