Hi,
The HL-L2360DW is a printer supporting the driverless AirPrint technology.
About AirPrint - Apple Support
To begin with, you may want to try the following procedure: Power off the router, the printer, the computer, and all other devices/computers. Wait two to three minutes. Power on the router. Wait two to three minutes. Power on the printer. Wait a minute or two. Power on the computer. Finally, power on all other devices/computers.
Also, this article could perhaps be of interest:
https://help.brother-usa.com/app/answers/detail/a_id/73618/~/compatibility-with-5-ghz%2C-dual-band-wireless-router%2C-or-mesh-networks
If applicable, check whether it is possible to, temporarily, configure the router to use 2.4 GHz only. Alternatively, use an old 2.4 GHz-only router, just for a test. Any difference?