Odd HTML output from Send-MgUserMail (V2.26)

[12Knocksinna]

Describe the bug

I am trying to send email with a HTML body. The message is sent, but the resulting HTML renders incorrectly in all the mail clients I have tried (Outlook classic, new Outlook, OWA, Proton). It looks as if the HTML can't interpret the u003c ("<") for some reasons.

The HTML content for the message is good and can be rendered by https://codebeautify.org/htmlviewer

Everything worked until I installed V2.26. Here's an example of a message sent on Wednesday Feb 19 with V2.25.

Expected behavior

I expect the Send-MgUserMail cmdlet to generate valid HTML text in the message body part that can be read by email clients.

How to reproduce

Create HTML content for a message. In this instance, a table is created from some data (could be Get-MgUser)

$SelectedUsers = Get-MgUser -Filter "userType eq 'Member'"
$MsgFrom = 'Customer.Services@office365itpros.com'

Define some variables used to construct the HTML content in the message body

HTML header with styles

$HtmlHead="
<style>
BODY{font-family: Arial; font-size: 10pt;}
H1{font-size: 22px;}
H2{font-size: 18px; padding-top: 10px;}
H3{font-size: 16px; padding-top: 8px;}
H4{font-size: 8px; padding-top: 4px;}
</style>"

$HtmlBody = $null
$HtmlBody = $HtmlBody + "

Users

"

$HtmlBody = $HtmlBody + ($SelectedUsers| Sort-Object DisplayName | ConvertTo-HTML -Fragment -As Table -PreContent "

Administrative alert: Inactive Teams based on 30-day lookback

")
$HtmlBody = $HtmlBody + "

These users are member accounts

"
$HtmlBody = $HtmlBody + "

Generated: $(Get-Date -Format 'dd-MMM-yyyy HH:mm')

"

$HtmlMsg = $HtmlHead + $HtmlBody + "

"

$MsgSubject = "Member users"

$ToRecipients = @{}
$ToRecipients.Add("emailAddress", @{"address"="office365itpros@proton.me"} )
[array]$MsgTo = $ToRecipients

Construct the message body

$MsgBody = @{}
$MsgBody.Add('Content', "$($HtmlMsg)")
$MsgBody.Add('ContentType','html')

$Message = @{}
$Message.Add('subject', $MsgSubject)
$Message.Add('toRecipients', $MsgTo)
$Message.Add('body', $MsgBody)
$Params = @{}
$Params.Add('message', $Message)
$Params.Add('saveToSentItems', $true)
$Params.Add('isDeliveryReceiptRequested', $true)

Send-MgUserMail -UserId $MsgFrom -BodyParameter $Params

SDK Version

V2.26

Latest version known to work for scenario above?

V2.25

Known Workarounds

None

Debug output

Click to expand log

```

</details>


### Configuration

Name                           Value
----                           -----
PSVersion                      7.5.0
PSEdition                      Core
GitCommitId                    7.5.0
OS                             Microsoft Windows 10.0.26100
Platform                       Win32NT
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0…}
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1
WSManStackVersion              3.0


### Other information

_No response_

[12Knocksinna]

I reverted to V2.25 and the code runs as expected.

[nathan-mhk]

I'm having this issue as well. All symbols are escaped to unicode.

[Tillsy]

Confirming this problem started for me a few days back as well. All my fancy HTML formatted automated emails using Send-MgUserMail are suddenly having unicode hex codes mashed everywhere in place of HTML tags.

[ryanchrisw]

Graph was already dumpster fire and now this. I guess this is what happens with you have Copilot write your code updates...

[Tillsy]

Holy %^#*^&$#@ this is way bigger than first though, a whole crapload of Graph APIs are suffering this problem even specifying a user via "username@domain" for a UserID in all the different commands fails with inability to deserialise :(. As @ryanchrisw said what a dumpster fire......

[ryanchrisw]

@timayabi2020 others can confirm for them but for me this is still not fixed.

[12Knocksinna]

Was a new version of V2.26 issued with the fix? No point in testing against the old and buggy software...

[Tillsy]

Reinstalled the modules just to be certain. Sending emails still whack, commands such as Update-MgUserContact fails to "deserialise" UserIds such as "blah@blah.com", significant problems my automations are all still down.