Error when send attachment more than 6MB to email

Where can we see the website in question?

I am experiencing an error when attempting to submit a form that contains attachments totaling more than 6MB in size

What error do you get?

See Setting up mail

What email settings do you have in the Mail tab panel?

To protect personal data, hiding email addresses in the settings or replacing them with dummy addresses is strongly advised. You can also include screenshots.

See this FAQ > After submitting the form, I get an error message stating “There was an error trying to send your message.” What is wrong?

Which border color do you see?

Then see this one > I get an error message with a red border. So, how can I solve this?

Perhaps you can find some clue in the PHP error logs. Ask your host support for help.