MySQL Proxy no longer working noticed when backend MySQL at version 5.7.43-47-log

When developing data analytical applications, the workstation needs to use MySQL-Proxy (version 0.8) to connect to the MySQL data source. This method has been working fine for years, however, we recently noticed that the connection is no longer working. The MySQL's version is 5.7.43-47-log, however, we are not one hundred percent sure whether it was due to the version upgrade. The issue is blocking our development, so we highly appreciate any hints and suggestions.