The error message you provided, PHP Warning: PHP Startup: Unable to load dynamic library 'gd.so'... undefined symbol: gdImageCreateFromAvif, suggests an issue with the GD (Graphics Draw) extension in PHP.

This error occurs when PHP is trying to load the GD extension (gd.so), but encounters a problem related to the gdImageCreateFromAvif function, which is likely missing or not properly linked.

To address this issue, you have a few potential options:

1. Recompile GD Library:

1. Download GD Library Source:

   • Download the source code for the GD library from its official website.

2. Compile and Install GD Library:

   • Follow the standard installation procedure for compiling and installing a library from source. This usually involves running configure, make, and make install commands.

3. Recompile PHP:

   • After installing the GD library, you may need to recompile PHP to link it properly with the newly installed GD library.

2. Check for Conflicting Libraries:

1. Check Installed Libraries:

   • Verify that there are no conflicting versions of the GD library installed on your system.

2. Remove or Update Conflicting Libraries:

   • If conflicting libraries are found, consider removing them or updating them to a version that is compatible with your PHP installation.

3. Verify PHP Configuration:

1. Check php.ini:

   • Ensure that the extension=gd.so the line is uncommented in your php.ini file.

2. Check Library Path:

   • Make sure that the path to the GD library is correctly set in your php.ini file.

3. Restart PHP:

   • After making changes to the php.ini file, you'll need to restart PHP for the changes to take effect.

4. Check for Updates:

1. Update PHP and GD:
   • Ensure that you're using compatible versions of PHP and the GD library. Updating to the latest versions may resolve compatibility issues.

5. Consult CloudLinux or PHP Support:

If you're using a hosting environment with CloudLinux or a specific PHP distribution, it's possible that they have specific recommendations or patches for this issue. Consider reaching out to their support for further assistance.

Always remember to back up your configuration files and data before making significant changes to your server's setup. This way, you can easily revert to a working state if any issues arise during troubleshooting.