There are many times that you added a wrong key to Office 2013 or you need to change the key.
Tag: office 365
Exchange Calendar Permissions using Powershell
This is a fast way to manage Calendar permissions of a mailbox. Same commands are for both Exchange on-premises and Exchange
Connect Powershell to Exchange Online
Connect PowerShell to Exchange Online $UserCredential = Get-Credential $Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://outlook.office365.com/powershell-liveid/ -Credential $UserCredential -Authentication Basic -AllowRedirection