There are several ways to solve this problem
The first solution: try reinstall all the server modules because maybe one of them has a problem
Second solution: Go to App Store and install one-click deployment . Once you have installed this module, open it, which is the last option to install WordPress automatically
Third solution: Manually install WordPress
First, create a folder called mepielan.gr in /www/wwwroot
Then, from the remote download section, download WordPress from https://wordpress.org/latest.zip to the desired folder
Now unzip the WordPress zip folder in a way that it is inside the mepielan.gr folder of the WordPress source (if the WordPress folder is alone, cut its contents into the mepielan.gr folder)
Now go to the database section and create a desired database
Then find the wp-config-sample.php file inside the mepielan.gr folder and rename it to wp-config.php
Open the wp-config.php file and enter your database information in the following sections
/** The name of the database for WordPress */
define( 'DB_NAME', 'database_name_here' );
/** Database username */
define( 'DB_USER', 'username_here' );
/** Database password */
define( 'DB_PASSWORD', 'password_here' );
