It appears you have an intermittent DNS issue since it is working some of the time. I recommend that you review the connections that failed and make note of the time to see if there is a pattern there. Since DNS is local, perhaps a server is having an issue or is down for maintenance. When a resource works at times and nothing is changing in GoAnywhere, it is best to look at the external resource, or in this case the DNS.
To help troubleshoot, you can run a short test project to connect to this resource repeatedly over time, then present the findings to your system admin and the remote server admin. If nothing changes in the GA resource, then something is changing elsewhere.
The DNS must not be the same for the production machine if the behavior is different. If nothing else, you may have to use the IP address if the name cannot be resolved.