Use this if one shared Microsoft 365 mailbox carries aliases across several domains — support@yourstore.com, support@yourstore.se, support@yourstore.de — and you want all of them in Commslayer.
Time required: 30–60 minutes, depending on how many domains you have
Not what you need?
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One mailbox, straight into Commslayer. Add your Outlook / Microsoft inbox → (10 minutes)
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One alias only. Microsoft 365 alias setup → (15–20 minutes)
Why you need one inbox per domain
Every email carries its original recipient address in the headers, and Commslayer uses that address to decide which inbox it belongs to. If only support@yourstore.com exists in Commslayer, mail to support@yourstore.se has nowhere to land.
Before you start
- Admin access to your Microsoft 365 account
- Access to the DNS settings for every domain involved
Step 1: Create one inbox per domain
Repeat for each domain, giving each inbox a name you'll recognise ("Support – SE"):
Note the forwarding address shown for each one — they're different, and you'll need them in step 3.
Step 2: Add DNS records for each domain
Each domain needs its own DKIM and Return-Path records, added to that domain's DNS.
Step 3: Enable external forwarding, then add a mail flow rule per domain
Microsoft 365 blocks external forwarding by default — turn it on first.
Then, for each domain:
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Sign in to the Microsoft 365 admin center
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Go to Admin centers → Exchange → Mail flow → Rules
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Click Add a rule → Create a new rule and name it after the domain
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Under Apply this rule if, select The recipient → address includes and enter that alias
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Under Do the following, select Redirect the message to and paste the forwarding address for that domain's Commslayer inbox
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Save, then repeat
Use Redirect, not Forward. Redirect preserves the original To: header, which is what Commslayer matches on.
Step 4: Test each one
Send a test email to every alias from an outside account. Each should appear in its own inbox.
Microsoft quirks
- Mail is landing in the wrong inbox. A mail flow rule is pointing at the wrong forwarding address — each domain has its own.
Once it's running, labels and teams keep the regions apart, and automation rules can auto-assign each inbox to the right people.
Anything else? Email troubleshooting →