Unable to download data to SMART Mobile

Hello !

I have noticed a very big problem with my SMART Mobile.
We are conducting a wildlife inventory of the Ndoki-likouala landscape in northern Congo.
We are using SMART Mobile 385 and SMART 7.4.
The SMART configurable model and application was loaded on the devices from my computer, and the download was also on my computer.
When the teams returned from the field, I started importing data through SMART Mobile, but it doesn’t work.
It shows me warning and error messages.
So when I download the data, it’s only a part of it that arrives. I lose the maximum amount of data collected in the field.
We use Blackview BV5500 plus, BV9500 and Ulefone AW3 devices.
In the case of the BV5500 plus devices, the data exists in the device, but can not be downloaded.
For the BV9500 and Ulefon AW3 devices, no data is present in the device, yet the data collection was well done in the field.

I need some help.

Thank you !!!