A lot of couples with a beneficiary coming from a third world country get denied at their K1 visa interview. In a lot of cases the US embassy/consulate doesn't even give an explanation, and this usually means that they don't believe that the relationship is bonafide and assume that it was established for immigration benefits. This happens especially when the relationship has other red flags too, for example huge age difference, huge cultural difference, different religions, etc. That is why in certain countries it isn't even worth to start a K1 process, since it will be more than likely getting denied. Ghana is one of the extremely high fraud countries, just like Nigeria, Pakistan, India. I suggest you to spend more time in person together. Not giving up, getting married and filing for a CR-1 visa shows long term commitment, so you will likely be approved this time.
Good luck!
