AirPrint on Brother Printer

I have a Brother DCP-L2550DW printer, which is never switched off and connected to my home WIFI.

My devices, Mac Mini, iPhone X and iPad (2017) are all connected to the same home network as my printer.

However, I realised that AirPrint detection is intermittent. After 1-2 days, there will be "No AirPrint Printers Found" on my iOS devices and maybe 1-2 days later, without me doing anything, my printer can be found again.

On my Mac, the Brother iPrint&Scan will show my printer in "sleep" mode while the Mac Printer & Scanner setting will show my printer to be offline.

I can safely assure that my printer remains connected to my home WIFI throughout as should it be disconnected, the WIFI button lighting would be blinking.

I have contacted the Brother service person who came down to provide support. He printed out some maintenance sheet and told me everything is normal. He told me to contact my router company, Linksys, to ask for help to disable IGMP Snooping.

I then contacted Linksys, who told me that my router, EA8100 has no IGMP Snooping feature. The Brother service person insists there is though after I informed him of my findings from Linksys.

I am kind of perplexed at what exactly is wrong with my AirPrint devices and printer.

I have removed my printer from my Mac and add it again on AirPrint, but it just does not seem to solve the issue. The only way to solve the issue is to power off and on the printer again.

Any kind souls able to assist?