Citrix have reported a major outage to their services:
'Citrix Cloud Platform Issues Impact All Services - investigating, 16 Jul 2018 4:50pm WEST
Citrix Cloud is currently experiencing issues that impact availability of admin and end-user services. We are working diligently to understand the root cause. At this point we believe the issue could be related to our third party provider and we are working to identify means of mitigation.
We will provide an update as soon as possible.'
Please check https://status.cloud.com for updates.