I had an exploratory informational interview set up with the hiring manager from an internal referral in mid 2017. At the time the level of the role potentially available was too junior for my experience. But we'd 'keep in touch.' Late 2017 the actual role at the right level was posted and they went radio silent after multiple rounds of follow up. Found out they were close to closing a candidate for that role, then they fell through and the same role was reposted in early 2018. (2x now) After follow up from my internal connection, they were sent my information a 3rd time. I had heard they also switched applicant tracking systems and may have lost my application? Regardless, it's unprofessional to go radio silent on an internal referral. Next time, respond saying they're not the right fit or the role has been filled.