The event logs on both ends may provide something useful.
2016 Datacenter - intermittent FQDN translation issues

Hello
Currently having intermittent issues with access to my three terminal servers working FQDN
Example
GPRO - 192.168.1.28
GADMIN - 192.168.1.29
GEXEC - 192.168.1.30
My users access these terminal servers through remote desktop and periodically users receive bad credential issues when accessing one of the terminal servers via FQDN (ie GPRO) however no issues when the access through the corresponding IP addy 192.168.1.28. This occurs randomly for all three terminal servers throughout the week but only for one of the term servers at any one time.
I have no DNS issues listed anywhere in my domain controller or through server manager on the three terminal servers.
I hope I explained this properly
Any assistance is greatly appreciated
Thank you
CS