Unable to send emails with attachment

This error is shoing up in the Email Queue:

File “/home/cadmus/frappe-bench/apps/frappe/frappe/utils/pdf.py”, line 98, in get_pdf
frappe.throw(_(“PDF generation failed because of broken image links”))

I don’t know where to find these broken links, I have checked my letterhead, and even tried deleting it. But as long as any email has a document attached, it does not send.

Is the attached file marked as private or public,

the attachment is a document. I’m attaching a sales invoice. I checked the the images in the letterhead, they are all public.

Does the PDF button work in Sales Invoice?

Yes. It does. PDFs are generated normally.

Which version of wkhtmltopdf do you have?

Are you using a reverse proxy or any local DNS “hacks”?

Have you seen this post related to wkhtmltopdf version and hostname?

Thanks. It turns out the site-name has to be the same url address. ie. if your url is going to be [site.something.com] then when creating the site name it the exact same thing [site.something.com].
However this implies I cant have multiple domain names pointing to the same site. Is this so?

Are you using DNS Multitenant or port based?

Have you seen adding custom domains? It seems you can create custom domains to act as an alias. I’m not sure how this behaves with PDF generation. I’d assume you’ll need an entry in /etc/hosts for each additional domain (which is true for multiple sites as well).