RabbitMQ: None of the specified endpoints were reachable
I get the None of the specified endpoints were reachable message in Diagnostic logs.
I checked and found RabbitMQ for Sitecore service is running but I can't access http://localhost:15672 to verify the QueueURI settings.
Did you try to restart the RabbitMQ service? I would try this first. This tool should always be working.
If this doesn't work, can you check the RabbitMQ logs. They would probably contains some errors. Update your question with the last errors please.