Hi Alexandre,

Thank you for buying our theme. We hope it will meet all your expectations! 🙂

We’re sorry to read that you’re facing such an issue. When you get an error 500, in most cases you just have to remove a plugin (or whatever else is causing the error) and your site would be back up and running again.

Unfortunately we can’t say exactly what was causing the issue, since we would need to read the debug logs from your website to get a more precise idea of what happened. To help us getting clues in case it happens again, please activate the debug logging on your website. Just turn WP_DEBUG to true, by pasting the following code lines (or replacing them if they already exist) in your wp-config.php file, just before the line that says ‘That’s all, stop editing! Happy blogging.’:

// Enable WP_DEBUG mode
define( 'WP_DEBUG', true );

// Enable Debug logging to the /wp-content/debug.log file
define( 'WP_DEBUG_LOG', true );

// Disable display of errors and warnings 
define( 'WP_DEBUG_DISPLAY', false );
@ini_set( 'display_errors', 0 );

Once it is done, please send us the debug logs from your website. More on this in the following topic: Debugging in WordPress

Finally, if you want to make backups of your website to save your work, we suggest that you read this article and choose the solution that fits you :
7 Best WordPress Backup Plugins Compared (Pros and Cons)

Best,