使用Gmail发送文件遇阻求助：更换账号密码仍未解决

Hey there, let's walk through the key checks to get to the bottom of your file-sending issue—since you've already tried switching accounts and passwords, we'll focus first on your suspected recipient address issue, plus other easy-to-miss culprits:

• Validate the recipient address first

  • Start with a simple test: send a plain text email (no attachments) to that exact address. If this fails too, the address is almost certainly the problem:
    • Double-check for typos: missing letters, swapped characters, or incorrect symbols (like using a . instead of @ is super common)
    • Confirm the recipient's email is active: it might have been deleted, suspended, or their account has strict spam filters that block incoming messages from unknown senders
    • Ask the recipient to check their spam folder, quarantine, or reach out to their IT team—some corporate email systems automatically block Gmail-sent messages, especially those with attachments

• Rule out attachment-related issues

  • Try sending a tiny test file (like a 1KB .txt document). If this works, your original file is the problem:
    • Check file size: Gmail limits single attachments to 25MB. For larger files, you'll need to share a Google Drive link instead of attaching directly
    • Check file type: Executables (.exe, .bat), encrypted files, or certain compressed formats might be flagged as unsafe by Gmail or the recipient's email provider

• Quick checks on your Gmail account setup

  • Even with a new account, if you're using a third-party app to send emails, make sure it's properly authorized via OAuth (Gmail no longer supports "less secure apps" by default)
  • Check if you've hit Gmail's sending limits: Sending too many emails in a short window can trigger a temporary restriction. Look for bounced emails in your "Sent" or "Drafts" folder—they'll include specific error codes explaining the block

• Dig into bounce messages

  • If Gmail returns a bounce email, don't ignore it! These include precise error details (e.g., 550 5.1.1 Recipient address rejected: User unknown) that will point you directly to the root cause—whether it's an invalid address, a spam block, or a server issue

内容的提问来源于stack exchange，提问作者Michael M1G0A4W