@Cornishman Check this forum topic to see if it applies to your friend's situation: https://community.tp-link.com/en/home/forum/topic/655034

@Jasper_Kimmel I am thinking you are buying additional Deco unit to add to your Deco mesh. This is how you add new Deco unit to Deco mesh: https://www.tp-link.com/en/support/faq/1590/ The rest should...

@Barney79 It could be, because: 1. Your son's mobile is not connected to Deco mesh, but uses cellular data or connects to someone's else WiFi network; or 2. Your son configured static IP address on...

@ClausBille Judging by IP addresses, your printer and PC are on different IP networks. To put them both on the same network, which will fix the problem, you will need to configure Deco mesh to run in...

@DavidAA Before Deco mesh, you must have had ISP modem to which HP printer was connected wirelessly. Do you still have that ISP modem in your home network and have you made any changes in its...

@Kuokhong Please also review the following forum topic to see if it applies to your situation: https://community.tp-link.com/en/home/forum/topic/655034