Problem: When you trying to send an email using Gmail account, an error prompt “Oops… a server error occurred and your email was not sent. (#76997)”.
Solution 1: Clear Browsing Data on Browser
For Mozilla Firefox
Step 1: Open Mozilla Firefox.
Step 2: Click on library-like button located at the top right part of the browser’s window.
Step 3: Navigate to History > Clear Recent History…
Step 4: Under the Time range to clear setting, choose Everything by clicking the arrow which will open the dropdown menu.
Step 5: Check at least Cookies and Cache, click on Clear Now.
Step 6: Restart browser.
For Google Chrome
Step 1: Open Google Chrome.
Step 2: Click on the three vertical dots in the top right corner of its window.
Step 3: Navigate to More tools > Clear browsing data.
Step 4: Choose the beginning of time setting as the time period and select at least cache and cookies to delete.
Step 5: Click on Clear data button.
Step 6: Restart computer and disconnect network from computer.
Step 7: Open Google Chrome, again click on the three dots and select Settings > Advanced settings.
Step 8: Open Content > See all cookies and site button.
Step 9: Click on Remove all button.
Step 10: Restart computer.
Solution 2: Log out Gmail Account then Login Again
Solution 3: Uninstall Google Earth
Step 1: Login Windows as Administrator.
Step 2: Go to Start > Control Panel > Settings app > click on Uninstall a Program under the Programs section.
Step 3: Click on Apps to open a list of all installed programs.
Step 4: Locate Google Earth entry and click on it once.
Step 5: Click on Uninstall button.
Step 6: Restart computer.
Solution 4: Add Exception for Google Servers for AVG
Step 1: Open AVG user interface.
Step 2: Right-click on the icon in the system tray and choose Open
Step 3: Navigate to Menu > Settings > Components tab.
Step 4: Click on Customize button next to the Web Shield entry and navigate to Exceptions tab.
Step 5: Under the URLs to exclude part type in the following entries: