The GD library is not installed on your server. This library is required to produce the sparklines. Please ask your system administrator or your web host to install php-gd for you. For more information, check the Matomo Diagnostics Check.

On linux, you can install php-gd by executing apt-get install php-gd on debian type systems, then restart your webserver.

If you are using Apache webserver and a module called mod_security, you may need to disable this mod_security module as it may sometimes cause Sparklines graphs to not display.

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