The following error can occur when initializing an xDB set:
ERROR xDB Cloud - Exception during initializing occurred
System.AggregateException: One or more errors occurred.
---> Sitecore.Cloud.RestClient.RestRequestException: https://discovery-xdb-cloud.sitecore.net/xdb/set/<LicenseID>?DeploymentId=<DeploymentID> failed
---> System.Configuration.ConfigurationErrorsException: The value of the property 'proxyaddress' cannot be parsed. The error is: Invalid URI: The URI is empty. (C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Config\web.config line 50)
at System.Configuration.BaseConfigurationRecord.EvaluateOne(String[] keys, SectionInput input, Boolean isTrusted, FactoryRecord factoryRecord, SectionRecord sectionRecord, Object parentResult)
This error is primarily related to a configuration issue in the global web.config file.
The global .NET Framework web.config file contains following entry under <system.net>:
<defaultProxy>
<proxy bypassonlocal="Unspecified" proxyaddress="" />
</defaultProxy>
To address the error described above, remove this entry from the global web.config file and reboot the IIS server. The Sitecore instance will then correctly initialize the xDB set as requested.