Writing to Android device

Until relatively recently I have been able to write and export directly
to my Android device, which allows me to read things in transit or
avoid lugging my laptop. However, somewhere along the line, I believe
in the LO-6.2 series, this has become impossible. Attempting to write
an odf file or export to pdf results in a "File does not exist" error,
followed by a "general input/output error".

The problem occurs in Mageia 7, E22 DE, currently with LO-6.2.3.2. Is
there perhaps a setting to cure this ill?

Cor, I've copied you as you helped so much on the save dialog issue.