It is the main point actually - you followed a V3 tutorial made for a product that is now outdated and no longer supported. Not everything made for V3 works exactly on V5 without modification, hence the reason the new V5 tutorials were made. Yes most things should work, but some things require modifications, that is why my first point has always been that you follow a guide for V5 and not for V3.
Your “main aspect of the post” actually was - you followed an outdated V3 tutorial on V5, it does not work as expected and crashes. Maybe you made a mistake in setup, or maybe there is an issue with that tutorial on V5. So it is right my first point to say is this, and if you checked over the newer V5 tutorials may resolve your issue (actually you can just delete the whole setup you did and use the auto configuration task to set up 99% of it for you). It doesn’t make a lot of sense to debug an old V3 instruction for V5 when there already exists a new version of the tutorial.
Maybe you think I’m wrong, but the fact is you followed a V3 tutorial, how you came across that considering you have been a forum user since July 2020 I am not really sure but nevertheless that is fact. SambaPOS do not support V3 or V4, and that includes tutorials made for those versions.
Also as Jesse said, you did not share enough details for us to assist with your issue, so if you could please share that - but I suggest you redo the setup with the auto configuration task or V5 tutorial as it will work better with the latest features that were not available in V3.