Shamim's Plugins

Can you please try only following code? (remove fep_admin_cap code)

add_filter( 'register_post_type_args', function( $args, $post_type ){
    if( 'fep_group' == $post_type ){
        $args['show_in_menu'] = true;
        $args['capability_type'] = 'post';
    }
    return $args;
}, 10, 2);

Let me know. This way you do not need to give other users admin access then modify by other plugin.

Can you please try following code along with above code

add_filter( 'fep_admin_cap', function( $admin_cap ){
    return 'manage_options';
});

Change capability here as well. This will give that user admin capability (eg. see all messages etc), so use with caution
Let me know.

It is a deprecated warning, So nothing to worry.
We will fix that in next version.

Add following code in your theme’s (child theme’s if you are using) functions.php

add_filter( 'register_post_type_args', function( $args, $post_type ){
    if( 'fep_group' == $post_type ){
        $args['capability_type'] = 'manage_options'; //Change this as you need
    }
    return $args;
}, 10, 2);

Let me know

It is always better to use a child theme for modification.

I tried your contact form and it seems it is working.
Can you please let me know what error you are getting?

Can you please add the default code in https://www.shamimsplugins.com/docs/front-end-pm/customization/send-welcome-message-user-register/ and see if it working? Then change to your code.

Please go to Dashboard > Front End PM PRO > Settings > General and correct “Front End PM Page”