Shamim's Plugins

Thank you.
When UserA will send an email, his email address will be in “From” email. In this method he will message to himself. We will need to find a way to determine UserB to whom that message will be sent.

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

add_action( 'fep_message_table_column_content_author', function(){
    if( 'threaded' === fep_get_message_view() ){
		?><span class="fep-message-author"><a href="https://yoursite.com/<?php echo fep_get_userdata( fep_get_message_field( 'mgs_last_reply_by' ), 'user_nicename', 'id' );?>/"><?php echo fep_user_name( fep_get_message_field( 'mgs_last_reply_by' ) ); ?></a></span><span class="fep-message-date"><?php echo fep_get_the_date( 'mgs_last_reply_time' ); ?></span><?php
	} else {
		?><span class="fep-message-author"><a href="https://yoursite.com/<?php echo fep_get_userdata( fep_get_message_field( 'mgs_author' ), 'user_nicename', 'id' );?>/"><?php echo fep_user_name( fep_get_message_field( 'mgs_author' ) ); ?></a></span><span class="fep-message-date"><?php echo fep_get_the_date( 'created' ); ?></span><?php
	}
});

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

add_filter( 'fep_filter_user_name', function( $name, $id ){
	if ( $name && fep_get_the_id() ) {
		$name = '<a href="https://yoursite.com/'. fep_get_userdata( $id, 'user_nicename', 'id' ) . '/">' . $name . '</a>';
	}
	return $name;
}, 10, 2);

When you reply to an email, does not goes to that email inbox which you set in POP3 email? Please do the following and let me know.
1. Create a new message
2. Reply to that email which is sent to recipient email address.
3. Check inbox of that email which is set as POP3 email. Does that reply in email inbox? Does that email has message key in email subject? Does that email sender email is same as that user email in your website?
4. Wait 15 minutes. Refresh your website couple of times. Does that email still in inbox of that email address? Is it imported as message in your website?

You can follow https://www.shamimsplugins.com/support/topic/allow-only-admin-to-message-groups/#post-36544

Hi,
You can follow https://www.shamimsplugins.com/docs/front-end-pm-pro/customization-front-end-pm-pro/change-templates/

Thank you for your suggestion. I have updated that docs page.
If you need my assistance anytime you can create a support topic.