How to troubleshoot: ERROR 1296 (HY000): Got error 122 'Cannot retrieve error message' from CONNECT

Hi. How can i troubleshoot error below?

"ERROR 1296 (HY000): Got error 122 'Cannot retrieve error message' from CONNECT"

Above error occurs if I select from a JDBC external table after using CONNECT engine JDBC tables to retrieve data for a day or 2.
How can I debug more?
I tried connect_xtrace=1023. Output goes to mysqld.log but not much info available to check further.
Also tried changing JDBC drivers & it's still the same.

I have MariaDB-server-10.3.21-1.el7.centos.x86_64.rpm installed. & am using MariaDB 10.3.21.

Thanks & best regards,
KH