Test suite collection execution fails

Consider in katalon having 4 test suites (4 different modules) and all test suites are given retry count of 2 for fail test cases and all 4 suites are added in one test suite collection called Regression testsuite collection.
On execution of 40 scripts from test suite collection consecutively 4-5 scripts fails always.
It can be any script.
Kindly need solution of how to solve synchronization issue in katalon…
What is the approach