Losing Volumio conection when using mobile hotspot!

Hi all,
I have been using Volumio for many years and there was up and down with it but I still like it the most of all other similar audio players. I’m using Volumio on Rpi 3A+. I have quite a big problem that I don’t know how to solve. Volumio is 99% of the time on my home wifi network. But a couple of years ago when I needed to move and I didn’t have internet in the apartment for a month I used my mobile phone and its mobile data and mobile access point instead of wifi. And there were no problems.That was about 5-6 years ago. Now I can’t convince Volumio to use my mobile phone data again without problems. I’ve tried everything in my power because I have a headless system but this just happens every time. When I start Rpi and Volumio boots up and starts using my mobile network, everything is OK for a certain time…a couple of minutes. After that, the connection simply disappears and I cannot use the application. I use macbook for Volumio management which also uses my mobile hotspot. Why is this happening? Is there an easy fix? And is there any other way to control the Rpi/Volumio laptop other than via wifi. This is the third day and I’m getting frustrated. Thanks in advance! Nikola