Hi friend!
The answer is all.
Main WLAN Interference Sources
The LAN works on the 2.4 GHz and 5 GHz frequency bands. Therefore, all WLAN interference sources, especially the 2.4 GHz frequency band, are likely to be interference sources.
The main interference sources are as follows:
Bluetooth, infrared sensors, microwave ovens, wireless phones, medical devices, etc.
Hope to help you!