Coherence and Truth
A belief-set can be coherent even if all of its members are false. The belief that your parents are aliens coheres very well with the belief that they keep a flying saucer in the garage, which coheres very well with the belief that the FBI have dispatched agents to investigate, etc. Despite the coherence of this belief set, however, none of these beliefs is true.
Justified beliefs, because they are justified, are more likely to be true; the whole point of seeking justification for our beliefs is that justification is truth-conducive. The mere fact that a set of beliefs is coherent does not imply that its members are true. In fact, there are more false coherent belief sets than there are true coherent belief sets. As justification is truth-conducive, though, while coherence is not, justification and coherence must be two separate matters. Coherentism is false.