Regex regex = new Regex(SiteUrl, RegexOptions.IgnoreCase);
            string strSiteRelavtiveURL = regex.Replace(fileUrl, string.Empty);
            string strServerRelativeURL = CombineUrl(web.ServerRelativeUrl, strSiteRelavtiveURL);
            //web.Context.Credentials = new SharePointOnlineCredentials(UserName, GetPasswordFromConsoleInput(Password));
            Microsoft.SharePoint.Client.File oFile = web.GetFileByServerRelativeUrl(strServerRelativeURL);
            clientContext.Load(oFile, o => o.Title, o => o.Name, o => o.ListItemAllFields);
            clientContext.ExecuteQuery();

how to resolve this issue in .net core
Below error is getting

System.Net.WebException: The remote server returned an error: (400) Bad Request.
   at System.Net.HttpWebRequest.GetResponse()
   at Microsoft.SharePoint.Client.SPWebRequestExecutor.Execute()
   at Microsoft.SharePoint.Client.ClientContext.GetFormDigestInfoPrivate()
   at Microsoft.SharePoint.Client.ClientContext.EnsureFormDigest()
   at Microsoft.SharePoint.Client.ClientContext.ExecuteQuery()