For Google Workspace.
For Microsoft 365.
What should I do when the mail content cannot be displayed in the Email Security's Temporary Suspension interface?
HENNGE One filtering service feature analyzes the sent mail structure to perform filtering processing and to display the text in the mail confirmation screen.
When the RFC noncompliant mail-data is sent and the mail structure cannot be analyzed, the text will not be displayed in the temporarily on-hold mail/ approved mail confirmation screen.
(*)The applicable E-mail data-structure/data-transmission-method are imposed by the RFC regulation.
Please be aware that there might be some cases when Google Workspace cannot properly judge the encoding of attached files if they are in the text format such as .txt or .csv type.
In such a situation, it is probable that the problem be solved by saving the text file in the “UTF-8” format before attaching onto the outgoing mail.
■The sample cases of Google Workspace misjudgment on the file text encoding
1) When the mail was sent with attached text file saved in “Shift-JIS” character code.
2) When the character code is declared as “US-ASCII” on the mail data despite that the attached file text’s character code is actually “Shift-JIS”, this will cause a discrepancy between the declared code and the actual one.
Content-Type: text/plain; charset=US-ASCII;(※)