My webshop is offline and gives error undefined class constant CACHEGROUP

I hope someone here is able to help me. I have no experience with technical issues in Magento. I am getting an error while starting my website. Somebody similar to this problem? Hope you can bring me online!


Fatal error: undefined class constant & # 39; CACHE_GROUP & # 39; in /home/deb126395/domains/ on line 1075