Could it be that the error consists of only two letters “xx” in a file name of TWRP Recocery?
TeamWin’s TWRP for Samsung Galaxy S6 edge has the code name “zerolte” while in /e/ documentaion it uses the code name “zeroltexx”.
The code name “zeroltexx” is also used in the section “Installing a custom recovery” and as link TWRP, although there is no download. Please also note my → note of 16.11.2019.