uncaught exception: Http Error #500

in file: /var/www/mml/wirisplugin/integration/lib/com/wiris/plugin/impl/HttpImpl.class.php line 61
#0 [internal function]: com_wiris_plugin_impl_HttpImpl_0(Object(com_wiris_plugin_impl_HttpImpl), NULL, 'http://www.wiri...', 'Http Error #500')
#1 /var/www/mml/wirisplugin/integration/lib/php/Boot.class.php(769): call_user_func_array('com_wiris_plugi...', Array)
#2 [internal function]: _hx_lambda->execute('Http Error #500')
#3 /var/www/mml/wirisplugin/integration/lib/haxe/Http.class.php(532): call_user_func_array(Array, Array)
#4 [internal function]: haxe_Http_5(true, Object(com_wiris_plugin_impl_HttpImpl), Object(com_wiris_plugin_impl_HttpImpl), Array, Object(haxe_io_BytesOutput), true, 'Http Error #500')
#5 /var/www/mml/wirisplugin/integration/lib/php/Boot.class.php(769): call_user_func_array('haxe_Http_5', Array)
#6 [internal function]: _hx_lambda->execute('Http Error #500')
#7 /var/www/mml/wirisplugin/integration/lib/com/wiris/plugin/impl/HttpImpl.class.php(27): call_user_func_array(Array, Array)
#8 /var/www/mml/wirisplugin/integration/lib/haxe/Http.class.php(444): com_wiris_plugin_impl_HttpImpl->onError('Http Error #500')
#9 /var/www/mml/wirisplugin/integration/lib/haxe/Http.class.php(458): haxe_Http->customRequest(true, Object(haxe_io_BytesOutput), NULL, NULL)
#10 /var/www/mml/wirisplugin/integration/lib/com/wiris/plugin/impl/HttpImpl.class.php(40): haxe_Http->request(true)
#11 /var/www/mml/wirisplugin/integration/lib/com/wiris/plugin/impl/RenderImpl.class.php(187): com_wiris_plugin_impl_HttpImpl->request(true)
#12 /var/www/mml/wirisplugin/integration/showimage.php(24): com_wiris_plugin_impl_RenderImpl->showImage('7aa17101f57dcd1...', NULL, Array)
#13 {main}