Error message

• Warning: simplexml_load_file(https://api.wunderground.com/weatherstation/WXCurrentObXML.asp?ID=ICYSYROS1): failed to open stream: HTTP request failed! HTTP/1.0 503 Service Unavailable in locccations_preprocess_page() (line 25 of /var/www/vhosts/therocket.gr/locccations.com/sites/all/themes/locccations/template.php).
• Warning: simplexml_load_file(): I/O warning : failed to load external entity "https://api.wunderground.com/weatherstation/WXCurrentObXML.asp?ID=ICYSYROS1" in locccations_preprocess_page() (line 25 of /var/www/vhosts/therocket.gr/locccations.com/sites/all/themes/locccations/template.php).
• Notice: Trying to get property of non-object in locccations_preprocess_page() (line 27 of /var/www/vhosts/therocket.gr/locccations.com/sites/all/themes/locccations/template.php).
• Notice: Trying to get property of non-object in locccations_preprocess_page() (line 28 of /var/www/vhosts/therocket.gr/locccations.com/sites/all/themes/locccations/template.php).