Dynamics Community Forum Thread Details

Dynamics 365: Error 0x80040278 ("Field Contains Invalid Characters") on Email Reply

Hi All,

We're encountering an intermittent error in Dynamics 365 when a user tries to reply to a specific email thread from within the application.

Error Message:

The field '[object Object],3' contains one or more invalid characters. Error code: 0x80040278

Behavior:

The error appears as a popup when the user attempts to reply to a specific email thread
The issue is not reproducible in UAT, it only occurs in production with a specific email conversation
Other emails work fine, it seems tied to a particular email thread

Questions:

Has anyone seen the [object Object],3 field name in this error before? Which field does it typically point to?
Can long or special-character email subjects (with / and ()) trigger 0x80040278?
Is there a known issue with deep reply chains causing this error in D365 email?
Could a custom plugin or JavaScript web resource on the Email entity cause this type of serialization error?

Environment: