Yes it can. I do it every day. Please provide more information on your situation. And please advise on who sent that notice. Thank you.

It was the mail delivery system from thunderbird saying undelivered mail. I only receive that problem when emailing gmail accounts. Thank you david

Was there any explanation? Gmail is very security aware. Posting the complete text of the response message may be helpful.

It said…. I’m sorry to inform you that your message couldn’t be delivered to one or more recipients. Then lists for more assistance to send the mail to post master

any attachments? is it to multiple recipients? If it looks like spam, it will be refused.

No it’s my customers email just one recipient, that I’m trying to send an invoice to. I’ve sent them invoices in the past but now it’s not working

As google are very specific about using the SPF framework as well as other server verification tools including reverse DNS to confirm senders. Your issue is probably with your mail hosting system. I am guessing you use a custom domain provided by a web hosting service as they are prone to D.I.Y. setups and incorrect configuration of email settings.

Please post the text of the response email verbatim. Google in my experience always include error codes and links for more information.