As mentioned above you need to make sure that when the Bolt server is running, it can access the project. This is because it will modify the versioninfo file to set the comments left in the threads on the Slack post.

Slack Post with Threaded Comment
Comment left in Slack as a threaded conversation to the original publish.

Prism Post with Threaded Comment
The same comment from Slack now posted in Prism as a comment to the original publish.