For debugging any issue in AEM the ideal way is to setup a JVM remote debugger, however if that is not an option you could try log tailing....
Following steps explain the setup and tailing an environment log in a cloud manager program using Cloud Manager Plugin for the Adobe I/O CLI. Check it on Github
Tailing logs is also available in an open source implementation of Cloud Manager Desktop
Install the Adobe IO Node.js Application
1) Open command prompt and install Adobe I/O CLI. More details on Adobe IO CLI here
npm install -g @adobe/aio-cli
2) Install the Cloud Manager Plugin. More details on the CM plugin here
aio plugins:install @adobe/aio-cli-plugin-cloudmanager