The app pops this message when it can't load the report. This usually happens if the report's memory footprint it too big for that specific device and the iPhone/IPad operating system if terminating the view that presents the report.
Can you work with the report creator or removing some pages or visuals from the page, to reduce the resouces required for loading the report?
It seems a bit strange to me as we haven't had any layout changes in 3 years. The Ipad is the same with the same settings and the only thing that has changed over time is the power bi mobile version. Old version it works well.