Not being able to attach Excel files in Gmail or other file types is not a rare situation. There are many reasons for this situation, such as unstable internet connection, your file type is blocked, the file size is too large. In addition to these 'culprits', it can also be caused by firewalls, browser you are using. Here are some specific solutions:
This is also an effective way to fix the error of not being able to attach files in gmail. To do this, the user presses the Windows + R key combination > Enter firewall.cpl and click OK > In the left column, click on the line Turn on or off Windows Defender Firewall (as shown).
Finally, you need to turn off Windows Defender firewall in the Domain, Private, and Public network settings. Then click OK to save.
Additionally, if the user has set up a web browser proxy, try disabling the proxy. Besides, if you are using third-party anti-virus software, please temporarily turn off this software. After that, send it back to gmail and attach the file to see if it works or not.
Users should ensure that they are using a supported browser. The familiar browsers you should use are popular browsers such as Chrome, Firefox and Safari, Microsoft Edge. Regardless of the browser used, users must enable cookies and JavaScript. In addition, you should update your browsers to the latest version (if available).
Besides the above tips, if the Email does not display attachments, the file cannot be attached. Then try clearing your browser's cache and cookies. Or change to another browser to log in to gmail. You can also use incognito mode to see if it works.
Above are some measures when the computer cannot attach files. If all of the above measures fail. Users should contact Gmail support for advice. Just click on the question mark next to the Settings icon (upper right corner of the screen) in the main Gmail interface on your computer > Select Help > Select 'Send feedback' and follow the instructions.
Hope you are succesful.