A file called cert.pem is required to successfully run the Aggregator with Secure Sockets Layer (SSL) certificate verification. 

If cert.pem does not exist and the Aggregator was initially installed as v1.7.30, then the Aggregator fails to run.

However, If cert.pem does not exist and the Aggregator has been upgraded from v1.7.29 to v1.7.30, then the Aggregator runs with no SSL certificate verification. This method is not secure, so it is  recommended to comple cert.pem configuration so that the Aggregator can run with SSL certificate verification.