Why I can't Send Emails with Attachments
Sometimes, while sending an attachment email, you might have faced the error message that your mail was not sent successfully. The issue of Gmail won't send emails with attachments might be caused because you have set up a web browser proxy. So, try disabling the proxy server. The other reason could be that the size of your attachment is too large. So, check with your email service provider to see the limits for your attachment files.
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