Geodirectory Add event to google calendar Plugin

functions.php

<?php 
add_shortcode( 'buddy-add-to-calender', 'buddy_add_to_calender' );
function buddy_add_to_calender( $atts, $content = "" ) {
	$event_id = get_the_ID();
	global $gd_post;
	$event_details = maybe_unserialize($gd_post->event_dates);
	$title = get_the_title( $event_id );
	if( !empty( $event_details['start_date'] ) && !empty( $event_details['start_date'] )){
		$start_date = $event_details['start_date'] .' '.$event_details['start_time'];
		$end_date = $event_details['end_date'] .' '.$event_details['end_time'];
//		$event_start_date = date('Ymd\\THi00\\Z', strtotime( $start_date ));
	//	$event_end_date = date('Ymd\\THi00\\Z', strtotime( $end_date ));
		$event_start_date = date('Ymd\\THi00', strtotime( $start_date ));
		$event_end_date = date('Ymd\\THi00', strtotime( $end_date ));
		$content = '<a href="https://www.google.com/calendar/render?action=TEMPLATE&text='. get_the_title() .'&dates='.$event_start_date.'/'. $event_end_date .'&details=For+details,+link+here:+'. get_permalink().'&sf=true&output=xml" class="add-to-calender" target="_blank" ctz="America/New_York"><i class="far fa-calendar-alt"></i></a>';	
	}
	
    return $content;
}