Check it, Ultimately, if you get a Bitly link sent to your messages and you can’t do the typical “check the domain” thing,
check the Bitly link by adding + to the end of the URL, and then look at the domain.
Else report to avast's, considering that site's reputation
https://sur.ly/i/bitly.com/and wait for a final verdict from avast team, as they are the only ones to unblock or declare it as a FP.
polonus