BME AI studio import data error BME690 8xshuttleboard e appl board 3.1

Good morning. I am using the BME690 8xshuttleboard with appboard3.1. For the acquisition of raw data I use BME ai studio mobile with Bluetooth connection. Once the data is acquired, I perform the conversion to .bmerawdata using the devkit v3-1-0 tools and then import the data into BME AI studio desktop. In the first few days of testing, I was able to import them correctly and then analyze them. For a few days, even following the same steps, I can no longer import the data and it gives me the error: “Data import failed. Raw data not be imported. The data appears to have been invalid  format..” I tried with BME Ai studio on 2 different computers, trying to resample the raw data and perform new conversions. What could be the problem?