that he gathered in the dossier - he stated that he believed 70-90% of the information to be true. I believe that the cohen visit was one that he wasn't able to independently verify (along with the pee tapes) - though there are still reports that cohens cell pinged in the area:
https://www.cnbc.com/2018/12/28/the-michael-cohen-prague-accusation-continues-after-sentencing.html
If you were ever really an investigator (which I'm skeptical of)...you would know that sometimes information is unverifiable - THAT DOESN'T MEAN THAT IT ISN'T TRUE OR THAT IT HAS BEEN PROVEN TO BE FALSE.
The majority of the information in the Steele Dossier was accurate.