There are several ways to access your Gmail account. You can use the mobile app, open it through a desktop email client, or access the web version. However, some users complain that they encounter the “Corrupted Content Error” when they try to open Gmail through the Mozilla Firefox browser.
If this happens to you, fortunately, there are ways on how you can fix the issue.

How to Fix Corrupted Content Error or Network Protocol Violation on Gmail and Firefox Web Browser
The Corrupted Content Error is a common problem in most browsers especially for Firefox. Some users experience the “Network Protocol Violation” error message instead. This particular problem also occurs when you attempt to open other websites aside from Gmail such as services like Spotify.
The complete error messages says:
“Corrupted Content Error
The site at https://mail.google.com/mail/u/0/ has experienced a network protocol violation that cannot be repaired.
The page you are trying to view cannot be shown because an error in the data transmission was detected.
Please contact the website owners to inform them of this problem.”
To help you solve the issue, try each of the solutions below and check if the error is still there.
#1 – Use Another Browser

Try opening your Gmail account using a different browser. The Corrupted Content Error may only occur on Firefox, so accessing your email through other browsers may work. Try out modern browsers like Microsoft Edge, Opera, Brave or even the good old Google Chrome.
#2 – Check Your Internet Connection
The problem may also be due to poor WiFi network connection. Perform a speed test of your home network and check if you have a good Internet connection. Once this gets out of the way, proceed with the next method.
#3 – Unregister Your Gmail on Service Workers Firefox Settings (If Applicable)

- On your Firefox browser, enter the following on the address bar: about:serviceworkers.
- Look for your Gmail entry. It may include the Gmail address.
- Below the Gmail entry, click the Unregister button.
- Restart your Firefox browser.
#4 – Clear Firefox Cache

- On the upper right corner of your Firefox browser, click the three-line icon or the Menu button.
- Select Options.
- Go to Privacy and Security.
- Look for the Cookies and Site Data.
- Click the Clear Data button on the right side.
- Check the boxes next to Cookies and Site Data and Cached Web Content.
- Hit the Clear button.
#5 – Update Your Firefox Browser

- Click the Menu button on your Firefox browser.
- Select Help.
- Choose About Firefox.
- Click the Restart to update the Firefox button.
- When prompted by the User Account Control, click Yes.
#6 – Clear the DNS Cache on PC
- Launch the Command Prompt (Admin).
- Enter the following: ipconfig /flushdn.
Which of the solutions above works for you? We want to know what is more effective. You can tell us in the comment section below.