website cannot be accesed

i installed zeetasty theme on my website https://www.jualstagen.com
it runs smoothly for about 2 months
today my website cannot be accessed (but my other websites on the same server can be accessed normally)
when i tried to change the theme into default wordpress theme (twenty fifteen), it can be accessed normally
but once i change my current theme into zeetasty again(because it is more beautiful than the default wordpress theme), it cannot be accessed again
is there any problem with zeetasty?