Symptoms:
On a (multi) project snapshot with issues creation Configuration Manager fails with an error similar to this.
Cause:
This can happen in case the system contains issue data that is disproportionate to the amount of system memory / heap size allocated on the environment. Refer to Atlassian's Jira sizing guide https://confluence.atlassian.com/enterprise/jira-sizing-guide-461504623.html
Resolution:
Refer to the following article and more specifically to increasing JIRA application memory for instructions how to resolve this issue.