Issue accessing home smart devices remotely

[Mike-w1]

Hi

I have a number of Wemo and SwitchBot devices I use to control heating / lights etc whilst away.  Until recently, I was able to activate / deactivate these devices when off of the wifi when I am away from home.

The devices are all connected to the WiFi (BT Hub 2) and can be operated by the device apps when I am on the WiFi network also.

when I disconnect my phone from the WiFi and go on to 4g, the apps can no longer operate the devices.  This worked fine until approximately 3 weeks ago.

I have tried disabling the firewall to test if there was something blocking traffic, but that had no effect.

any ideas?

[countrypaul]

How are you trying o access your devices, using an ip address or via a DNS provider - if the external ip address of your router has changed have you updated the ip address you are using, or has the DNS entry updated and propagated? There have also been cases of BT blocking certain sites and BT  DNS servers not resolving those addresses if yo attempt to resolve the DNS entry (if you are using one) does it work on your LAN using the BT DNS servers and if ot does it work if you try Google or Cloudfare DNS servers? What mobile network are you using?