After further investigations i’ve found the culprit code below

 /**
 * Email login support for bp-branded-login plugin
 */
add_filter( 'wp_authenticate_user', function( $user ) {

	if ( isset( $_POST['log'] ) && ! is_email( $_POST['log'] ) ) {
		return new WP_Error( 'invalid_email' );
	}

	return $user;
}, 10 ); 

Please can this be improved to prevent invalidation of email addresses with spaces at the back

Thanks

I just deactivated all plugins and noticed that its a login problem and not registration issue wordpress is not allowing logins with spaces after the email address. The error message (invalid email) is being displayed. Will it be possible to display a custom error message in the login form when a user mistakenly adds a space after their email address during login. The custom error message should be (Sorry, this email is invalid. Email addresses cannot contain spaces.) Since the space is invisible the user still thinks that their email address is correct but this custom error message will point out the cause of login failure.

I am also using the branded login plugin