Virtual Agent does not load for non-logged in users on Service Portal

When non-logged in users access the Virtual Agent (chatbot) in Service Portal it does not load for them.

They get stuck in the page that displays "Connecting" message.

1. Activate Glide Virtual Agent (com.glide.cs.chatbot) plugin
2. Without logging into the instance navigate to <instance-name>/$sn-va-web-client-app.do
3. Notice Virtual Agent loads and is working normally
4. Activate Explicit Roles (com.glide.explicit_roles) plugin
5. Without logging into the instance again navigate to <instance-name>/$sn-va-web-client-app.do
6. Notice Virtual Agent is stuck on loading while displaying the "Connecting" message

This issue is caused by non-logged in users failing the OOB ACL "GlideAMBProcessor" because public role is not added to it.

Resolution would be to navigate to System Security > Access Control (ACL) > Search for a record where Name = GlideAMBProcessor. On the Requires role embedded list add in the "public" role and save the record.