Hi there,
Finding the reason for the issue without a log might be a bit tricky and the Dashboard.log will not expose any info. The below thread discusses the same issue and you can try out some troubleshooting steps from this and see if that helps you to sort the Issue. If these workarounds are of no use we can then use tools like sysmon to find the source.
Remote Web Access An error occurred while setting up your domain name https://learn.microsoft.com/en-us/answers/questions/355521/remote-web-access-an-error-occurred-while-setting.html
Are the problems with remotewebaccess.com domain and Dynamic DNS service? https://learn.microsoft.com/en-us/answers/questions/318584/are-the-problems-with-remotewebaccesscom-domain-an.html
An error occurred while setting up your domain name https://learn.microsoft.com/en-us/answers/questions/344980/an-error-occurred-while-setting-up-your-domain-nam.html
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