Emails with attachments not being delivered

Is there any way to look into where emails generated by workflows may be getting “hung up”.

I have a workflow that generates an email with than attachment. The attachment is a pdf generated through a template. The workflow always triggers when it is supposed to. the email is always created, and the attachment is always created. According to the log the “Result”: “Success” though the email never shows up, when you check the email details in the log I get the message: “Failed to fetch email details. Please try again later” even when you check it 24 hours later.

Is there any way to check if the email is getter rejected by the receiving server? I am assuming that it is getting sent.

Please contact for help with this.