oday, a customer told me that one of users cannot success to sync emails at his phone, I tried to use Microsoft Remote Connectivity Analyzer to test Exchange ActiveSync Connectivity, it has no issues with Exchange ActiveSync Autodiscover but not Exchange ActiveSync, it failed to attempt the FolderSync command on the Exchange ActiveSync session and error message is “Exchange ActiveSync returned an HTTP 500 response (Internal Server Error).”.
As we know, starting on November 15, 2017, outbound email messages that are sent directly to external domains (such as outlook.com and gmail.com) from a virtual machine (VM) are made available only to certain subscription types in Microsoft Azure. Outbound SMTP connections that use TCP port 25 were blocked. (Port 25 is primarily used for unauthenticated email delivery.), so you will notice the VM at Azure won’t send out email.
Have you been followed my previously blog to build up Hyper-V nested virtual machine on Microsoft Azure? If you don’t, you better build it right now, because this is pre-requisites and you will get lots of benefit for your lab or even production environment, you can reference this link and build it. If you did, congratulation! You can create a nested gest virtual machine and install Firewall (e.g. Sophos XG, Fortinet…) for free, why we still need to build firewall at our Azure Hyper-V nested environment? Because it supports lots functions that we cannot get the functions for free from Azure, e.g. server load balance, firewall, SNAT, application filter, IPS…and so on, we also can use it for LAB or simulate issues or POC. I am going to show how to build Sophos XG here.