Thank you for confirming this information, @MM2020! A Video Doorbell 2 and a compatible mechanical chime kit are often a straight forward and problem free configuration. As this worked for 2 years, with no problems, let’s check wiring first. Please ensure wires are connected securely to the Doorbell and chime kit, as well as check for any erosion, fraying, or exposed wiring that might lead to a short. If Cat5 or thin wiring is being used, this wiring can have problems with delivering voltage properly over time.
Considering the age of the chime kit being used, as well as the transformer, is always a good step. This will help to ensure the chime is receiving the power it is rated for and the transformer is still providing that power, adequately, to both the chime and the Doorbell. Sometimes, switching the two wires on the back of the Video Doorbell, can help with a more stable connection.
If this concern persists, feel free to send pictures of wiring so we can take a closer look, or reach out to our support team. If you are wanting to troubleshooting more in-depth, please give our support team a call at one of the numbers available here. We’re taking additional steps to protect our team and help reduce the spread of COVID-19, so this has resulted in longer than normal wait times. If you are outside of the US, please read our response to COVID-19 here to see how to contact support.