Most of the issues related to email sending with Outlook are due to Microsoft technical limitations or security rules. You can find all the main reasons here as well as answers to your potential questions.

Table of contents

My emails stopped being sent

In general, sending emails is only interrupted when Outlook stops us to do so. There can be several reasons for this.

Outlook integration is disabled

1. Your password has been modified

If you have recently changed your Outlook/365 password, your integration will be disabled because the connection will no longer authorized. To correct this problem, set up the Outlook integration again to create a new connection.

2. An admin set up two-factor authentication (2FA)

When an admin enforces 2FA after you have already set up a connection, your integration will be disabled because the connection is no longer authorized. To correct this problem, set up the Outlook integration again to create a new connection.

3. Upfluence connection was revoked on Outlook

You or an Admin can revoke Upfluence's ability to interact with your Outlook account. This is done via Outlook. If you've done this by mistake, simply set up a new integration using your account credentials. If an Admin on your Outlook account has made this change, you must reach out to your Outlook Admin or your IT department.

4. Connection expired

The last possibility is that your connection was inadvertently broken. This can happen when your connection expires. To correct this problem, set up the Outlook integration again to create a new connection.

Daily sending limit

According to Microsoft, there are different limits on how many emails you can send from your Exchange, Outlook & Office 365 business accounts.

Outlook and Basic Office 365

Outlook and Basic Office 365 users generally do not have defined rate limits:

  • These can vary based on how many users are on your domain and how old your team is.

  • The limit is based on your account reputation.

  • The limit is lower for new accounts and when has spotted what it deems suspicious activity

Exchange and Office 365 Business accounts

Microsoft restricts you to 10,000 daily recipients. This limit works on a rolling timer, rather than a daily timer, which means that your Outlook email recipient limits will reset 24-hours after you’ve reached them, rather than at 12 a.m. the next day.

For example, a user sends an email message to 5000 recipients at 09:00 AM, then sends another message to 2500 recipients at 10:00 AM, and then sends another message to 2500 recipients at 11:00 AM, hitting the limit of 10,000 messages. The user won't be able to send messages again until 09:00 AM the next day.

If you know you have reached your daily sending limit, you will need to wait until the next day in order to send more emails.

Outlook account verification

If you are facing this error message, please read the following instructions:

Before you can send emails, Microsoft will need to verify your account. Please follow the instructions provided by Microsoft in your online mailbox.

For email addresses that have just been created, Outlook has implemented "anti-spam" security to prevent emails from being used for mass emailing.

  • If you have just created your Outlook account, you are likely to receive an error message when you want to send your first emails with your Outlook email address.

  • If you receive an error message, it is necessary to check your Outlook account after 1 and 10 emails sent with the email address.

We suggest that you warm-up your email address by sending about ten emails before you start using it in Upfluence.

I can't connect my Outlook/365 account

It's likely that your account is currently not able to integrate. This integration only works if you have a Microsoft online exchange inbox and not on a dedicated Microsoft Exchange Server. To confirm this please visit this site, if you're able to connect this means you have an online exchange account, if you're unable to connect and receive an error message this means you don't have an online exchange account and you won't be able to use this integration.

Note: we do not support aliases or group emails (like for example). There is no mailbox attached to this kind of email addresses 😊

Note: If you have any additional questions or need any additional clarifications, please let us know at or contact your account manager using the Intercom chat.

Please make sure to send us a screenshot of the error message you're seeing in both and

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