How to fix a broken CAPTCHA in the login screen: EventLog Analyzer on Linux
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Issue description
When you have enabled a CPATCHA on the login page of Linux using EventLog Analyzer's Logon Settings, you might face an issue where the CAPTCHA image seems to be broken. This article provides step-by-step instructions to fix the issue.
Possible causes
- Browser Cache
- Missing fonts required for rendering the CAPTCHA in the Linux server
The broken CAPTCHA image issue is often the result of either a browser cache problem or missing fonts required for rendering the CAPTCHA. Since Linux distributions typically do not include Microsoft fonts by default, you may need to install them manually.
Prerequisites
- Access to the EventLog Analyzer user interface.
- Access to the Linux server on which EventLog Analyzer is installed with root or similar permission to install a package.
Steps to follow
1. Access the EventLog Analyzer user interface in an incognito/private browser window to check if the issue is related to the browser cache. If so, clear the browser cache to resolve the issue.2. If the issue persists, it is likely caused by missing fonts required for rendering. To install the necessary fonts, open the terminal and run the following commands:
sudo apt install fontconfig
This command installs Fontconfig, a library and command-line utility used by Linux systems to manage and configure fonts. It enables font discovery, font substitution, and automatic fallback for missing fonts.
sudo apt install ttf-mscorefonts-installer
This installs a set of Microsoft TrueType core fonts, such as:
- Arial
- Verdana
sudo fc-cache -f
This command forces a refresh of the font cache used by Fontconfig.
- -f indicates "force" the rebuild, even if no changes are detected.
- This ensures that any newly installed fonts (like the Microsoft fonts) are detected and available to applications.
3. Once the required libraries and fonts are installed, restart the Linux server once to have them applied.
4. Reload the login page in a private/incognito browser window to verify.
If the issue persists, contact support with required details (listed in the section below).
Tips
To verify if the fonts have been successfully installed, run the below command
fc-match Arial
This tries to find a font on your system that matches Arial. If the exact font isn't available, it returns the closest fallback (e.g., Liberation Sans, DejaVu Sans, etc.).
fc-match Verdana
This is same as the above command, which checks for Verdana.
How to reach support
- You can submit a ticket through our official support portal or you can reach out directly via email at eventlog-support@manageengine.com.Find contact information for EventLog Analyzer support.
- In order for us to effectively help, include the below details so we can understand the issue better.
- A screenshot of the EventLog Analyzer license page.
- A screenshot of the login page showing the broken CAPTCHA issue captured from an incognito/private browser window.
- A screenshot of the Console tab from the browser's developer tools.
- To access it: Right-click on the login page, click Inspect, and go to the Console tab.
- A screenshot of the terminal output for the following commands:fc-match Arialfc-match Verdana
- Product logs:EventLog Analyzer Serverout logs: <EventLog Analyzer Home>\logs\serverout_20xx-xx-xx.txt (Most recent file)EventLog Analyzer Catalina logs: <EventLog Analyzer Home>\logs\catalina_20xx-xx-xx.txt (Most recent file)
