thumb bo 5

The nut is somehow screwed on sideways( shown in the picture). Ive tried to loosen it but it doesnt move at all. I have no idea if the jack is original or if it has been replaced since im not the original owner. Any tips are greatly appreciated :)

Yesterday we (my band 2Faces - U2 coverband) played at a Dutch festival. I used my Thumb BO5, live sound via DI, no eq. During "Still haven't found what I'm looking for" a vocal group passed by and joined the song! Hope you like it als much as I do! Sietze