Unable to start its own HTTP listener

On a few laptops in the workshop the participants are getting an error message upon launching Bloom. You have to launch 3 times to open the application, but the first 2 times they get the following error:
“Bloom was unable to start its own HTTP listener that it uses to talk to its embedded Firefox browser. It this happens even if you just restarted your computer, then ask someone to investigate if you have an aggressive firewall product installed, which may need to be uninstalled before you can use Bloom.”
One of the laptops is brand new, typical configuration with W10, Windows Firewall on, and Windows Defender as anti-virus. We uninstalled Firefox and Thunderbird to see if that was the culprit but no joy. Any ideas?

Hi Darcie,
Would love to look at that machine via remote desktop (Bomgar). Hit me up if that’s possible.

How was this issue resolved, John? I keep getting this error and Bloom can’t run. My friend from Nigeria is complaining about the same issue on a few computers that he is supporting. It is happening with version 4.6.1 and 4.7.106.

Hi David,

How was this issue resolved, John?

I’m sorry, someone in Cameroon linked up with Darcie and I don’t have a record of what they did. We have 21 reports of this happening in our database; very rarely does a user reply when we answer and try to help, so we don’t know a lot about the problem.

The message you get when this happens is still our best advice:

Bloom was unable to start its own HTTP listener
that it uses to talk to its embedded Firefox browser. If this happens even
if you just restarted your computer, then ask someone to investigate if you
have an aggressive firewall product installed, which may need to be
uninstalled before you can use Bloom.

As far as I know, if this problem persists even after restarting, it is always caused by some non-Microsoft antivirus or firewall. Looking through our reports, I see that last year in one case it was Kaspersky & another it was Malware Bytes.

jh