No specific reason for UK visa refusal [duplicate]

My UK visa refusal letter came back without a specific reason for refusal that I can rectify the next time am applying and for the record I don't see any reason for refusal coz I provided both my father and the other sponsor's official employment letters , pay slips and bank statements covering the last six months. My father takes care of me here in my home country where we both leave and my other sponsor who is my aunt is UK citizen and she was the one supposed to care of me in UK as she stated in the invitation letter and the sponsorship under taking form. Am a full time university student so I don't work, I provided my university enrollment certificates and a letter from the dean stating I was free to travel because its the official university holidays given that I come back in time when studies resume so that I can finish my third and final year Am always in touch with my aunt coz she usually visits us here and we regularly chat so I also provided screenshots of our WhatsApp chats I show that we keep in touch. So I don't know the exact reason why my application was refused that I can rectify the next time I apply. They only told me the change the circumstances of my application and check Appendix V