I uploaded an excel file to my board ten days ago and was given the option to import it as a table or post it notes.  All worked fine.

Today I tried to upload the same file again (as I had added mew data while offline) and the file just uploads as a pdf! I tried dragging and dropping from my desktop and uploading via the upload button on the board, No difference, it treats the file as a pdf!

The excel file is only 24kB so not large.  What might be the problem?