Explanation
The transmit power settings of the access point determine how strong the Wi-Fi signal is. If the transmit power is too low, the Wi-Fi network will have slow connection speeds and poor coverage. If the transmit power is too high, the Wi-Fi network will interfere with other nearby networks and devices, causing congestion and performance issues. Therefore, the technician should check the transmit power settings first and adjust them to an optimal level for the office environment.
References:
*8 Reasons Why Your Internet is Slow (and How to Fix It), section "You have weak Wi-Fi signals".
*6 Things Slowing Down Your Wi-Fi (And What to Do About Them) - How-To Geek, section "Channel Congestion Dings Wi-Fi Performance".