Relaunch the web browser. Try closing and reopening the application.
Try clearing the cache and cookies via the Internet settings.
For Google Chrome, you may find the Internet Settings on the top-right part of your screen (Icon with the three vertical dots) > Click History > Click History again > Click on Clear browsing data > Choose the time range > Click Clear Data
You may also navigate via the Google Chrome Settings option: Internet Settings on the top-right part of your screen (Icon with the three vertical dots) > Click Settings > Scroll down to Privacy and security > Click on Clear browsing data > Choose the time range > Click Clear Data
For Internet Explorer, you may find the Internet Settings on the top-right part of your screen (Gear Icon near the Favorites and Home Icons) > Click on Internet options > On the General Tab, navigate to the Browsing history section > Click on Delete... button > Click Delete > Click OK or Apply
For Mozilla Firefox, you may find the Menu Settings on the top-right part of your screen (Icon with the three horizontal lines) > Select Options > Select the Privacy & Security Panel > In the Cookies and Site Data section, click Clear Data > Click the Clear button
You may also navigate via the Firefox Library button (Icon with books on the upper-right corner of the window) > Click History > Click Clear Recent History... > Select the time range you prefer > Click the Clear Now button
Try performing a Disk Clean-up. See above for the step-by-step instructions on how to perform this.
You may also check the LAN Cable to see if you have internet connection.