Error while tranfer photos by Adobe Send

Hi  While Adobe Send worked without any problems until last week, now every transfer aborts with message "One or more files could not be transferred - retry"

I thought first some of my files were corrupted and wasted a lot of time - without success...

Now. I just tried transferring  2 other files from another computer running another OS - and got the same result--- 😞

What to do ?

Regards

Charles