Many users have reported a problem with the MX Master 3 cutting out and disconnecting at random. This leads to a very poor user experience and can be very frustrating if you’re trying to be productive.
Here are a few tried and tested solutions to the problem.
Check the battery
Make sure that the battery is charged. The battery level of the MX Master 3 is indicated by an LED on the mouse.
There is only a single green LED. So you really don’t know how much battery is left. Only that it is charged.
This is not like the older MX Master 2s that has a battery level indicator so you know approximately how much charge is left on the mouse.
You can also check the battery status in Logi Options application which shows three levels at the bottom of the app window.

Clean the sensor
Over time the Optical Darkfield sensor under the mouse collects dirt. This could result in the mouse cutting out at random. To resolve this, the sensor needs to be cleaned.

Move any USB 3 devices away from the Mouse
USB 3 ports tend to be very noisy and cause RF interference especially when they are in heavy use. An example is when you might have an external disk connected to your laptop over USB 3.

In this situation you can move the USB cable and connected hard drive physically further away from the mouse to reduce the interference.
Use a USB Extender Cable
As the mouse moves further away from the dongle, the strength of the communication signal between the two decreases.
Use a USB extender cable to move the USB dongle closer to the mouse. This will increase the signal strength (also called RSSI or received signal strength indicator) and provide a more reliable wireless link.
Move Wireless Router
Wi-Fi routers transmit very strong wireless signals that interfere with the operation of wireless mice. The primary reason for this is that they occupy the same 2.4 GHz frequency band. Move any nearby access points or routers away from where the MX Master is being used.
Change the Wi-Fi Band
Most Wi-Fi routers operate on the 2.4 GHz band by default. This is the same frequency range that is used by the MX Master mouse. As a result signals from your router interfere with signals between the mouse and the USB dongle.

You should be able to configure your router to operate on the 5 GHz band. This will reduce the amount of interference to the MX Master mouse.
Summary
In this post we have presented the reader with 6 potential solutions to the problem of a wireless mouse cutting out. These solutions can be applied to any mouse. Although in this post we have focused on the MX Master 3 / 3s which is very popular.