Can't Send Attachments with Send-MgUserMail (V2.26)

[12Knocksinna]

Describe the bug

I can't add multiple attachments to a message. The error is:

Error sending message: [RequestBodyRead] : Cannot convert the literal '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...' to the expected type 'Edm.Binary'.

This worked before I upgraded to V2.26... and the code that I used is discussed in https://office365itpros.com/2025/02/19/add-attachments-email/.

Expected behavior

I expect Send-MgUserMail to be able to process and send attachments.

How to reproduce

See the code used in the article above to create and send a message with multiple attachments.

SDK Version

V2.26

Latest version known to work for scenario above?

V2.25

Known Workarounds

Maybe use the Graph request?

Debug output

Encoded attachment makes full debug log impractical.

        "contentType": "applicationvnd.openxmlformats-officedocument.presentationml.presentation",
        "name": "Exchange PowerShell and the Graph.pptx"
      }
    ],
    "body": {
      "content": "Some important reading for you... Please note the large number of attachments and the size of some files!",
      "contentType": "html"
    }
  }
}


DEBUG: ============================ HTTP RESPONSE ============================

Status Code:
BadRequest

Headers:
Cache-Control                 : private
Vary                          : Accept-Encoding
Strict-Transport-Security     : max-age=31536000
request-id                    : 4d3051c0-029d-4cb5-879b-71c0346de28c
client-request-id             : 39a35852-fde0-4acb-8603-df2c6586fbb1
x-ms-ags-diagnostic           : {"ServerInfo":{"DataCenter":"North Europe","Slice":"E","Ring":"4","ScaleUnit":"003","RoleInstance":"DB1PEPF0001F858"}}
Date                          : Fri, 21 Feb 2025 13:57:09 GMT

Body:
{
  "error": {
    "code": "RequestBodyRead",
    "message": "Cannot convert the literal '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...' to the expected type 'Edm.Binary'."
  }
}


Send-MgUserMail_Send: Cannot convert the literal '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...' to the expected type 'Edm.Binary'.

Status: 400 (BadRequest)
ErrorCode: RequestBodyRead
Date:

Headers:
Cache-Control                 : private
Vary                          : Accept-Encoding
Strict-Transport-Security     : max-age=31536000
request-id                    : 4d3051c0-029d-4cb5-879b-71c0346de28c
client-request-id             : 39a35852-fde0-4acb-8603-df2c6586fbb1
x-ms-ags-diagnostic           : {"ServerInfo":{"DataCenter":"North Europe","Slice":"E","Ring":"4","ScaleUnit":"003","RoleInstance":"DB1PEPF0001F858"}}
Date                          : Fri, 21 Feb 2025 13:57:09 GMT

Configuration

No response

Other information

No response