Students do not enjoy reading in English because they do not understand the basics of English well enough. When we do not know the basics of spelling, vocabulary and grammar it is impossible to understand.  When you don't understand, how can you enjoy it?
 
Not only in a foreign language, but even when we read in our native tongue, if there is a key word that we do not know, it becomes difficult to understand the meaning of that sentence. If you miss the meaning a sentence, then there are chances you will not understand the whole paragraph. If you skip one paragraph, it is hard to make sense out of the rest of the reading. Students often continue reading without understanding the material. The result will be frustrating and students will be discouraged.