Found it! Hope it works for you.
This procedure requires 2 phones, or a tablet/ipad and a phone
Phone A / Tablet should have the app installed on it and phone B is to be used as the WiFI hotspot.
For iPhone:
i) Phone B: Temporarily rename the iPhone as the router network name. (in settings -> general -> about)
ii) Phone B: In the iPhone Wi-Fi Hot spot settings set the router password as the hotspot password.
iii) Temporarily switch the router off.
iv) Phone A/Tablet: Link the phone with the app to the iPhone hotspot
v) Carry out the pairing.
vi) Phobe B: Switch the Wi-Fi hotspot off
vii) Switch the router back on.
viii) Phone B: Rename the iPhone to its original name.
For Android:
i) Phone B: Go to the settings menu
ii) Phone B: Select Hotspot
iii) Phone B: Set the Wi-Fi hot spot name to be the same as the router network name
iv) Phone B: Tablet: In the Wi-Fi Hot spot settings set the router password as the hotspot password.
v) Temporarily switch the router off.
vi) Phone A/Tablet: Link the phone with the app to the Android hotspot
vii) Carry out the pairing.
viii) Phone B: Switch the Wi-Fi hotspot off
ix) Switch the router back on.
