There are two quick and easy fixes for this.
1. Change the battery, we cannot over emphasize the importance of having a BRAND NEW, good quality (Duracell, Energizer etc.) battery in these transmitters, they can be quite picky.
2. Set all of your switches in both the transmitter and chime (the switches which control the channel) to the “Down” or “Off” position. This is their default position and more often than not solves any intermittency issues.