There is a clash between the Dynatrace and APM agents and if the Dynatrace agent is already loaded, the APM agent can not be initialized.
You can check if the Dynatrace agent is loaded by running:
lsof -p <pid of application>
Check the output for a line similar to the following:
java 23615 ins mem REG 253,0 2535041 9556 /opt/dynatrace/oneagent/agent/bin/184.108.40.20600707-160955/any/java/oneagentjava.jar
This indicates that the Dynatrace agent is already loaded.
APM Java Agent 10.7
UnInstall the Dynatrace agent and restart the application and check that the APM java agent starts writing logs to AGENT_HOME/logs and is visible in the APM UI.
Also, see the following link: