Close and Outlook: what syncs, what doesn't, and how to set it up
Close connects a Microsoft 365 mailbox and calendar natively. Email syncs both ways and meetings come in from Outlook. Microsoft admin consent can block the connection, and contacts and leads are not part of it.
- Connector
- Native connected account built into Close, connected from Settings > Accounts & Apps; no add-on fee listed in the docs
- Sync direction
- Two-way for email and Done/archive status; Outlook → Close for calendar meetings; Close → calendar app for a task feed
- Setup time
- 5 minutes per user; allow about 30 minutes more if an admin has to change SMTP settings
- Availability
- All Close plans (Solo and Essentials allow 3 connected accounts per user, other plans 10); Microsoft plan requirements are not stated in the docs
- Our rating
- 4 out of 5. Two-way email and Outlook meeting sync on every Close plan; Microsoft 365 admin consent and SMTP settings can block the first connection.
| What | Direction | Detail |
|---|---|---|
| Emails sent from Close | Close → Outlook | Close sends through your own mailbox over SMTP. The message appears in your Outlook Sent folder. |
| Emails sent or received in Outlook | Outlook → Close | Close logs any email in your Sent folder, however it was sent. It attaches mail to a lead when the address matches one of its contacts. |
| Email history | Outlook → Close | Close imports past emails once a contact's address is added to a lead. A large mailbox can take several hours. |
| Done and archive status | Two-way | Marking an email Done in Close archives it in your mailbox, and archiving in the mailbox marks it Done. A per-account toggle turns this off. |
| Calendar meetings | Outlook → Close | Meetings show on the lead and in the Inbox sidebar. Close syncs an event only when an attendee's email matches a contact on a lead. |
| Task calendar feed | Close → calendar app | Close's Microsoft 365 listing says reps can subscribe to a calendar feed of their Close Tasks. The listing gives no setup steps. |
| Replies from other addresses | Derived | Close attaches a reply from a different address to the lead. This fails if the original email went to two or more leads. |
Setting it up
- In Close, open Settings > Accounts & Apps, click + Add Account and choose Microsoft.
- Click Connect with Microsoft and accept the permissions prompt, which includes calendar access.
- If Microsoft shows "Administrator approval required", ask an Entra admin to run the same flow once and tick "Consent on behalf of your organization".
- Back in Close, switch on email sending and email syncing. Switch on calendar syncing under Calendar Configuration if you want meetings.
- If sending disconnects, enable Authenticated SMTP in the Microsoft 365 admin center under Users > Active users > Mail > Manage email apps. Wait about 30 minutes, then reconnect.
- If mail doesn't sync, check that your Microsoft primary email and username match the address in Close. Enable IMAP on the same screen, then remove and re-add the account.
Where the integration stops
- Calendar permissions are required even if you skip calendar sync. If your Entra tenant withholds them, Microsoft blocks the whole connection, email included. An Entra admin has to approve Close.
- Authenticated SMTP must be on for the mailbox. If it is off, the account disconnects when you send and the email stays in the Close outbox. Microsoft can also disable SMTP AUTH for the whole tenant.
- Only events with a matching contact sync. Close filters out internal and blocked domains. It cannot hide one recurring event, so remove the contact's email from the event.
- Internal email is filtered by default. Excluding other domains means contacting Close support. The docs name Growth and Scale admins for that filter service, though the same page also lists older plan names.
- Shared inboxes cannot be added directly. Add the shared address as an alias to send. To sync inbound mail, forward it to your Close secret address.
- The docs cover email and calendar only. They don't describe contact or lead sync with Outlook. Close's integrations page points to Zapier or Make for apps without a native connector.
Close's Microsoft connector links an Office 365 mailbox and calendar to Close. It suits teams that work in Outlook and want every customer email logged on the lead. Close builds it into the product as a connected account, and the docs list no add-on fee. Check the Close pricing page for plan details.
The fact that surprises teams sits in the permissions prompt. Close asks for calendar access even if you never turn calendar syncing on. If your Microsoft Entra tenant withholds that access, the whole connection fails, email included.
Email syncs both ways, for contacts on leads
Close sends and syncs mail through your own mailbox over IMAP and SMTP. Mail you send from Close lands in your Outlook Sent folder. Mail you send from Outlook gets logged in Close with no BCC.
Close attaches an email to a lead only when the address matches a contact. It skips mail between coworkers. Marking an email Done in Close also archives it in Outlook, and the reverse works too.
If you use Gmail on part of the team, see Close and Gmail. The Outlook connector follows the same email model.
Calendar sync runs one way and needs a matching contact
Close reads your Outlook Calendar through Microsoft Graph. It shows meetings on the lead page and in the Inbox sidebar. A reminder bar appears 5 minutes before the start.
The connector doesn't create or edit Outlook events from Close. Close's docs describe only meetings coming in. An event syncs only when an attendee's email matches a contact on a lead.
Microsoft settings decide whether the first connection works
Two settings cause most failed connections. The first is app consent. In a managed tenant, an Entra admin has to approve Close, and the permission list in Entra does not refresh on its own. Close updated its Microsoft app registration in August 2026, so reconnecting accounts may see a new consent prompt.
The second is Authenticated SMTP. If it is off, Close can read the mailbox but can't send. The fix takes a few clicks in the Microsoft 365 admin center, then about 30 minutes of waiting.
Ask your Microsoft admin about both before you roll Close out to the team. For records Outlook doesn't touch, such as contacts or leads, the connector offers no route. Close's docs point to API-key tools instead, covered in Close and Zapier. See also the Outlook integrations overview and the Close vendor page.