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Archive for the ‘Exchange’ Category

When moving mailboxes to Exchange Online. The remote server returned an error: (503) Server Unavailable… mrsproxy.svc is unavailable, service is too busy or no endpoint.

I spent many hours troubleshooting and opening several support tickets with Microsoft, but in the end, I was able to fix the problem on my own. I believe it would be helpful for others to share my documentation of these procedures. The help from Microsoft O365 support was quite disappointing. They seemed to repeatedly ask the […]

Exchange 2013/2016 Outlook and OWA Search Does Not Work

As with all previous versions of OWA, Exchange 2013 and Exchange 2016 have a search function that is above the mail column, as seen below. When you do a search in OWA 2013, no results would be showing, no matter what information is the search keywords. No matter what, no search results were found. In Exchange 2013, the […]

How to fix 550 5.7.520 Access denied, Your organization does not allow external forwarding.

By default, Microsoft 365 Defender sets up an Anti-Spam outbound policy. And the policy default sets Automatic Forwarding to “Automatic: System Controlled.” Error: “Remote Server returned ‘550 5.7.520 Access denied. Your organization does not allow external forwarding. Please contact your administrator for further assistance. AS(7555)” Since we do not want to modify this default policy, […]

Last Error: Message deferred by categorizer agent.

Exchange 2013 mail flow issue. It turned out to be the Malware agent causing the issue Once it is enabled and the Exchange transport service is restarted, all emails are stuck in the submission queue with “Last Error: Message deferred by categorizer agent.” Check the mail queue Get-Queue -Identity submission Get-Transport Agent will list all […]

Exchange ActiveSync iOS Device

Updated: May 2021 iOS devices unfortunately do not register with ActiveSync or other tools with a logical clear human-readable version number. Instead, they show up with strings like “Apple-iPhone3C1/902.206”   Obviously, this makes discovery and reporting difficult.  To help ourselves, and the community at large, we now maintain this list of hardware and iOS versions for […]

Email spoofing

The goal of email spoofing is to trick the user into thinking an email is from a known and trusted source. Spoofing is done through the manipulation of email elements that are visible to the recipient, primarily the “Body From” field. A spoofed email can be partial or full: Partial Spoof: A partial spoof occurs when […]

Cannot send large messages via ActiveSync, iPhone/iPad

SYMPTOMS When sending from a Mobile device via the ActiveSync service the device fails to send. Some devices may return an error indicating that “The message that was sent to the server was rejected because the message was too large”. (Apple iPad iOS). Not all mobile devices behave this way and may just keep the message […]

Enable Automatic Replies, Out Of Office, for another user or additional mailbox

Admin Method 1: Exchange PowerShell If you are an Exchange administrator, then using the Set-MailboxAutoReplyConfiguration Exchange PowerShell command is the supported and native way to go to enable Automatic Replies without logging on to the mailbox itself. Set-MailboxAutoReplyConfiguration -Identity <username> -AutoReplyState Enabled -InternalMessage “Internal auto-reply message.” -ExternalMessage “External auto-reply message.” Admin Method 2: Exchange Admin Center Another way to […]

MS Exchange email won’t download on iPhone

I can’t seem to download emails on my iPhone, can sign into OWA and get it working on any version on Outlook, but it won’t download email on iPhone. I’m able to successfully configure the email on phone but when I go into the mail app, and try to download the emails, I get an […]