Dashboard page throws PHP exception

When trying to access /admin/content/translation-management/dashboard on my site, I get a PHP error message "The website encountered an unexpected error. Please try again later."

In watchdog the error is logged with this message:

Exception: String could not be parsed as XML in SimpleXMLElement->__construct() (line 153 of /www/git/htdocs/sites/all/modules/contrib/translation_management/icl_core/icl_core.webservices.inc).

I am using ICanLocalize as a translation service and the dashboard was available and functional for several days now. Suddenly it stopped working. No modifications to the site's code have been made. I'm running Pressflow 6.22.