@Boman This model is only available in Europe, have you review the specifications to see if the unit works with the operators/carriers? Contacting the operators/carriers to see if they support this...

@PieterWiid I recommend downloading the User Guide and follow the manual to review the LAN setup, along with DHCP and Internet. Possibly review the Security portion, where the MAC filtering is in...

@b.zoltan Product documentation is available at tp-link website, www.tp-link.com. Additionally, a quick search of the web would have yields the below link, which includes the User Guide manual....

@Spaceboy Was the router setup with VPN? The mobile devices used VPN while connecting to wifi on the router? The issue seems to be at the mobile devices end, firewall / VPN, and not the router...

@Nick2019 Have you log into the router web/management interface and setup the router, Internet parameter, to match that of the old router? Was any quick installation or user guide manual follow? From...

@m-lce Attempt the following, one at a time to see which works: Review the Wireless setting, under 2.4GHz, adjust the Mode, b/g/n or b/g or n only. Next, perform similarly with the 5GHz setting if...