Posterior distribution of the lens mass, distance, lens light if it was a MS star and allowed blend light obtained using method outlined in Sect. 5. Top: lens mass versus lens distance estimated from MCMC samples for Gaia18cbf for the best fitting model using the Gaia and follow-up data with u₀ < 0 and including a microlensing parallax effect, called GF−. Bottom: blended light magnitude from the microlensing model versus the light of the lens expected if the lens was a MS star. The dashed line separates dark lens or remnant solutions from MS star solutions. The colours are the probability density shown on a logarithmic scale.