DatebookHikariCP - Exception during pool initializationcommysqljdbcexceptionsjdbc4CommunicationsException Communications link failureThe last packet successfully received from the server was 18936 mil

This error message indicates that there was a problem initializing a connection pool to a MySQL database. The specific error is a "CommunicationsException" which usually means that there was a problem communicating with the database server. The last packet sent and received from the server were both several seconds ago, indicating a possible network or server issue. The exception was thrown during pool initialization, which means that the connection pool was not able to establish a connection to the database and therefore could not be used by the application. This could be caused by a variety of issues, including network connectivity problems, database server issues, or configuration errors in the application or connection pool