メール関係でのエラー

• Undeliverable mail -- (Undelivered): 554 5.4.7 >>> [internal] exceeded max time without delivery
• An error occurred when attempting to parse HtmlEmailBody content for HTML content.
• Syntax error when forwarding email
• Attribute "data-gr-ext-disabled" on element is not allowed, or has an invalid value.
• Error on a Lightning Email template: Attribute "data-autofill-highlight" on element is not allowed, or has an invalid value.
• Attribute "data-autofill-highlight" on element is not allowed, or has an invalid value.
• メール不達（NDR）コード
• Apexを使ったメールの操作など
• Emails to one or more recipients have bounced before. Check email addresses to make sure they are valid.
• Why Can't User See Email Signature Image?
• 添付ファイル付きのSalesforceでメールを送信するときにコンテンツ配信エラーが発生する

• INSUFFICIENT_ACCESS: insufficient access rights on cross-reference id: 005 テンプレートのフォルダーにアクセスできないため

• Send List Email: Hmm, that didn't work. Please try again in a bit.
  

• Attribute "data-gr-ext-disabled" on element is not allowed, or has an invalid value.

• フローのメール送信 insufficient access rights on cross-reference id

受信者Idに　Emailとメールアドレスが設定されているのが問題だと思います。
ここは!LOOP.Id　ではないでしょうか？

We couldn't find the record you're trying to access. It may have been deleted by another user, or there may have been a system error. Ask your administrator for help.

• Email Reply, Reply All and Forward throwing error

I actually found that one and could not locate the Global Action to assign it to the proper target. After a Salesforce ticket, turns out it was something they had to enable on their end.

https://help.salesforce.com/s/articleView?id=000387906&type=1

"TSS04" error in Yahoo

• Error Codes of Email Sends

Please check this article.

https://portal.smartertools.com/community/a92500/yahoo-error-421-4_7_0-delivery-delays.aspx