@KevinCH Hello, terribly sorry for all the inconvenience caused in this case, but don't worry that we will try our best to figure it out. Can I confirm your network layout again? Modem--->Main Deco...

@Raiden Hi, I have sent you a personal message, please check and see if it helps.

@TonyReilly Hi, thanks for all the details. Just follow up, what is the link speed on your computer or phone when you are testing the wireless speed which is no more than 360M down? Have you...

@HarlanPepper Hi, yes, they can still build up the mesh network between those Deco units. No worries.

@Omg7788 Hello, Our engineer will email you, if you are willing to do further analysis, please check your inbox and respond. Thanks for your cooperation and support. Good day.

@SM-xgrm Hi, you may refer to the below guide to switch the 2nd Deco M5 to the main Deco: https://www.tp-link.com/support/faq/2400/ BTW, I want to confirm again, if the Deco M4R connected to the main...