There's nowhere near enough info in the question to provide a sure answer to your problem, but there are clues pointing to possible issues. To figure it out, you should start by shutting off Little Snitch and the built-in firewall. Short Question Im thinking about configuring little snitch to allow all processes incoming and outgoing network traffic. By allowing 'any process” incoming / outgoing rights will this make my Mac less secure than its default settings (default out of the box, eg. Not using OSX’s in built firewall tool). If I remove access to the imagent ports 443 and 80. And try to send a iMessage on my Mac via Little Snitch. These are what Little Snitch will ask for. You can also use Little Snitch to check what FaceTime ports it is using. Just remember these are for out going. Using Little Snitch, it reported when Messages is fired up, the following: And for posterity, here is what the 'FaceTime' application reports as connections, since you can call it up from Messsages (camera icon next to user you're messaging's name): If anyone finds anything different, please add to this answer. (Making it community wiki). To figure it out, you should start by shutting off Little Snitch and the built-in firewall. You probably will want them back on eventually, but they should be off while you are trying to get complex services working to assure that they are not able to cause secondary blockage. Rule suggestions are created for these connections and can be reviewed in Little Snitch Configuration. If you can’t login without network access (e.g. Network accounts), the system can be restarted in Permissive Mode where all connections are allowed before the first user logs in. Allow-rules are automatically created so that future logins.
Starting with macOS 10.15.4 the above “Legacy System Extension” message will be shown when Little Snitch is installed.
→ Please read this blog post to learn more about why this message is shown.
Will there be an update of Little Snitch that’s compatible with macOS 10.16?
Yes. We are going to release Little Snitch 5 later this year, which will be compatible with macOS 10.16. → Learn more…
Will I get the update for free?
Yes. All licenses sold now include a free upgrade to Little Snitch 5. In addition, customers who purchased Little Snitch 4 within a one-year period prior to the final release of Little Snitch 5 will also get a free upgrade. → Learn more…
Little Snitch Can't Login Into Imessage Free
Will Little Snitch 4 run on macOS 10.16?
Little Snitch Can't Login Into Imessage Email
Little Snitch 4 will not be loaded on macOS 10.16 by default, but there will still be an option to allow the loading. → Learn more…