Cannot Install plugins

Cannot install plugins, and themes via WPMU DEV Dashboard plugin, getting:
Server error status: error [504]

Debug log is throwing the following error:
[29-Dec-2017 06:18:02 UTC] [WPMUDEV API Error] 4.4 | cURL error 28: Operation timed out after 15001 milliseconds with 22550 bytes received ((unknown URL) [500])