System is unable to email report error

I got the following error message today while running some tests.

System is unable to email report. Reason: net.sf.jasperreports.engine.JRRuntimeException: java.lang.OutOfMemoryError: GC overhead limit exceeded

I am using the docker image from: Docker Hub
following the instructions from GitHub - katalon-studio/docker-images: Docker images for Katalon Studio and other frameworks

This is being executed via our Jenkins instance, which has a lot of RAM (20+ GB) and hard drive space (100+ GB) free. I recieved the emails for the 4 tests executed in the test suite collection (shown in the following log).

**13:58:40** -------------------------------------------------------------------------------- 
**13:58:40** Test Suites/TF_TA Test Suite Collection - 20190608_155337............78/78(100%) 
**13:58:40** -------------------------------------------------------------------------------- 
**13:58:40** Test Suites/TF_TA JDC Validations - Firefox - 20190608_155339........37/37(100%) 
**13:58:40** Test Suites/TF_TA New Hire Validations - Firefox - 20190608_155341...17/17(100%) 
**13:58:40** Test Suites/TF_TA Reappointment - Firefox - 20190608_155343..........12/12(100%) 
**13:58:40** Test Suites/TF_TA Transfer - Firefox - 20190608_155344...............12/12(100%) 
**13:58:40** -------------------------------------------------------------------------------- 
**13:58:53** Jun 08, 2019 5:58:53 PM net.sf.jasperreports.engine.fill.JRFillSubreport prepare 
**13:58:53** SEVERE: Fill 3: exception

I was surprised to get the error message in the first place since as I mentioned I got my emailed reports.

Any ideas as to why it would issue an error about being unable to send an email (when it did send the expected 4 already?) Or does anyone know if there is a --config flag I can set to increase the access to memory?