I think this is a vague statement to say the least. It will be easier to answer if you would add some context (citation). Misfiring can be produced through an experimental intervention or in a pathological state and would be simply translated to not firing correctly. In other words, action potentials of the neurons are not generated as they normally would. Again what that means depends on the context, because the citation could refer to direct spike timing or encoding of information or many other parameters.
I faced the below statements and expression of "Dopaminergic Neurons Misfiring" was not understandable to me.
"A number of attempts have been made to explain the link between altered brain function and schizophrenia. One of the most common is the dopamine hypothesis, which attributes psychosis to the mind's faulty interpretation of the misfiring of dopaminergic neurons"