Thanks for the response Johao.
I have tried it with two different users. One has MFA enabled and the other does not. I use the other use by running the plugin reg. tool using "run as another user".
I've installed it on my home computer and the plugin reg tool works perfectly fine. But on a new work computer it doesn't work at all either on work network or not. I am wondering if I have installed something else that is interfering with this, however it shouldn't be giving an unhandled exception.
The log file is below
Source : Microsoft.Xrm.Tooling.CrmConnectControl
Method : QueryOnlineServerList
Date : 25/03/2020
Time : 10:48:28
Error : Method not found: 'System.String Microsoft.Xrm.Sdk.Discovery.OrganizationDetail.get_Geo()'.
Stack Trace : at Microsoft.Xrm.Tooling.CrmConnectControl.CrmConnectionManager.QueryOnlineServerList(ObservableCollection`1 svrs, OrganizationDetailCollection col, ClientCredentials liveCreds, Uri trimToDiscoveryUri, Uri globalDiscoUriToUse)
at Microsoft.Xrm.Tooling.CrmConnectControl.CrmConnectionManager.FindCrmOnlineDiscoveryServer(ClientCredentials liveCreds)
at Microsoft.Xrm.Tooling.CrmConnectControl.CrmConnectionManager.ValidateServerConnection(CrmOrgByServer selectedOrg)
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Thanks