Can't use custom prefixes

[Tamo73]

I changed my custom prefix to "-" a while ago and it worked fine until today, and only the "@mention" prefix is working.
I tried to change the default prefix and it didn't work either, even when I use other alt prefixes (I tried "+", "*" and "!" as alt prefixes). I also tried changing the default prefix directly from the config.txt file, but it stopped working with anything but the default "@mention".
I attached an image showing the problem.
Thanks for the help!

[jagrosh]

#1207

[Tamo73]

Weirdly enough, the option was on, but after toggling it off and on and restarting discord it worked fine again. Thanks!