EWS API throws error “No Mailbox with such GUID”

Recently i was working with an ISV/application developer, who created this custom application using EWS (Exchange Web Services) API. It worked with the account with impersonation rights to access other mailboxes/calendars in Azure/Office 365/Exchange Online. But when they tried to access a specific mailbox calendar, they see the error “No mailbox with such GUID”. We…


Hotfix: Failure Sending mail error with System.Net.Mail (.Net Framework 4.0) while sending large attachment

Recently one of my customer ran into an issue with his application used to send email messages using System.Net.Mail.SmtpClient (SNM) API. He used Visual Studio 2010 and .NET Framework 4.0. It’s a pretty simple code, //Sample C# code snippet using System.Net.Mail API SmtpClient MyClient = new SmtpClient("mail_server"); MyClient.Credentials = new System.Net.NetworkCredential("User", "Password", "Domain"); MailMessage MyMsg…

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