Strange Networking problem

I am facing a strange network issue with home assistant.

Firstly, I have setup the Home Assistant with a few sensors with raspberry pi 3 with the InfluxDB and Graphana interfaces.
This is working perfectly fine.

Secondly, I setup duckdns and gave access to all these 3 UIs (Home Assistant, InfluxDb and Graphana) over the internet.

I have separate 2 WLAN connections in my house and I am able to access all 3 webages using both the WLAN connections with duckdns as well as by directly typing the IP address.

Now comes the strange part.
If I go out of the house and try to use my phone or tablet to access my duckdns site using cellular data connection, the page does not load.

If I am able to connect to the webpages using 2 separate WLAN connections (RaspberryPi on WLAN1, Laptop to read on WLAN2) then it means that I am able to access it over internet.

But this fails over cellular data.!!!

What could be causing this?

Secondly, I setup duckdns and gave access to all these 3 UIs (Home Assistant, InfluxDb and Graphana) over the internet.

From above I take it that you forwarded the correct ports on your router? if 8123 is accessed from your outside IP (WAN IP you would setup with duckdns) your request if forwarded to your raspberry’s (LAN) IP?

And on both your phone and tablet you have setup the duckdns adres (and not the LANIP) afterwhich you cleared your cache before trying?

Thanks, I was able to resolve this.
My duckdns IP address somehow got changed inspite of setting it correctly.

I had probably not saved it.
Once I corrected this, I was able to use it properly.