Troubleshoot the connector

7 minutes

The Office 365 Outlook Connector in Power Automate is a powerful tool, but as with any integration, issues can arise. This section explores common challenges that you might experience, and it provides practical solutions to troubleshoot and resolve them effectively. From poorly formatted input to debugging tips, these guidelines can help you keep your flows running smoothly.

Missing or incorrectly formatted email addresses

Problem: Emails fail to send because recipient fields (such as To, CC, or BCC) are empty or incorrectly formatted.

Solution: Check the dynamic content or expressions that populate these fields. Ensure that valid email addresses are provided, and if you're using input fields, confirm that users are entering data correctly. Before using an email address in a recipient field, you could check it for validity. Numerous external connectors with email address validation actions are available, but you can do basic validation natively in Power Automate. In a Compose action, enter the following expression:

and(
    contains(variables('emailAddress'), '@'),
    equals(length(split(variables('emailAddress'), '@')), 2),
    contains(split(variables('emailAddress'), '@')[1], '.'),
    not(startsWith(split(variables('emailAddress'), '@')[1], '.')),
    not(endsWith(split(variables('emailAddress'), '@')[1], '.'))
)

The variables('emailAddress') part of the expression is the value of the email address to validate. You could replace the variable with another dynamic field. Then, you can use a Condition to confirm that the Compose action evaluated to true. While this expression isn't 100% comprehensive, it's highly likely that a value that gets past it is a valid email address.

Incorrect date formats

Problem: Calendar-related actions fail due to invalid date or time formats.

Solution: The connector requires dates in the ISO 8601 format. Use the formatDateTime() expression to ensure that dates and times conform to the format, for example: yyyy-MM-ddTHH:mm:ssZ.

A breakdown of the format is as follows:

yyyy - Year (such as 2025)
MM - Month (01–12)
dd - Day of the month (01–31)
T - Separator indicating the beginning of the time portion
HH - Hour in 24-hour format (00–23)
mm - Minute (00–59)
ss - Second (00–59)
Z - Indicates that the time is in Zulu or UTC (Coordinated Universal Time)

For example, 2024-12-05T17:47:42Z represents December 5, 2024, 17:47:42 (or 5:47:42 PM) in UTC time.

Large attachment handling

Problem: Flows fail when you attempt to send emails with large attachments that exceed the file size limit (25 MB for Office 365).

Solution: Implement a file size check in the flow. Use the Get file metadata action to retrieve the file size and add a condition:

If the file size exceeds 25 MB, skip the attachment or notify the sender.
Provide alternative solutions for large files, such as uploading the file to OneDrive or SharePoint and then sharing the link in the email body.

Invalid attendee addresses

Problem: Calendar event creation fails because attendee email addresses are invalid.

Solution: Begin by validating the email address that's being passed to the Attendee field. See the email address validation solution in the first section of this unit. If the attendees should be part of your company directory, you could use an action like the Office 365 Users action Search for Users (V2) to confirm that the email address corresponds to a valid user in your directory.

Overlapping events

Problem: Flows create events that overlap with existing ones, causing scheduling conflicts.

Solution: Use the Get calendar events action to retrieve existing events for the same time range. Add a condition to check for conflicts and then take appropriate action, such as notifying the user or rescheduling the event.