Shamim's Plugins

didn’t you tell them that you had added this code before this things happen?
All they had to to is remove this code from where you added and add again in appropriate location, nothing else.

Please access your website and remove that code from where you added. Then activate all your plugins and your theme.
Then let me know. I will add that code again in appropriate location for you.

This code is tested before giving you.
So either you php version is less then 5.3 or you had added this code in wrong place.
i can assist you if you give me your cpanel or file manager access.

assuming your php version 5.3+
Add following code in your theme’s functions.php (child theme’s if any)

add_filter( 'fep_eb_email_legends', function( $legends, $post ){
	$legends[ 'sender_username' ] = array(
				'description' => __('Sender Username', 'front-end-pm'),
				'where' => array( 'newmessage', 'reply' ),
				'replace_with' => ! empty( $post->post_author ) ? fep_get_userdata( $post->post_author, 'user_login', 'id' ) : ''
				);
	return $legends;
	
}, 10, 2);

Then go to Dashboard > Front End PM > Settings > Emails. use {{sender_username}} to send username in emails.

your theme should allow admin-ajax.php. There should be any option or any other way to allow this call.
Please contact your theme author.

My phone also have 4.0.4, so that is not an issue.
Please check your phone if there is enough memory or network problem or any other problem.

in my test website i have sent 1 pdf file and 1 png file and download from android phone. Everything working perfectly.

Can you please make a test user in your website and send some attachments. Then give access to me So that i can try.

When non admin user try to access your website admin area they see a error that they do not have permission to access. Which plugin show that error message?