Error in Email Sent with Attachment On Version-14

While sending mail with an attachment from the version-14 server showed error: frappe. exceptions.ValidationError: PDF generation failed because of broken image links. If I sent it forcefully from Email Queue it will be sent with an attachment.
Anyone experienced this problem Please share a solution, Thanks in advance.

follow the below steps for the error solution.
add “host_name”:“” in site_config.json
sudo apt-get install aptitude
sudo aptitude install libssl-dev
bench --site add-to-hosts