Good afternoon,
After checking that our nameservers are working properly, please try the following steps:
If none of these actions solve your issue, feel free to contact me again.
Thought process: I checked the dashboard and everything was ok and up-to-date with the configuration and the nameservers. Not having any logs associated with this question, it is most probably either a web browser issue, network connectivity issue/slowness leading to a timeout of the DNS query, or the user's computer may need to be restarted.