[WPMUDEV API Error] 4.1.0

I think its coming from WPMU Dashboard
in the error_log in root saw this.
[15-Jun-2016 16:30:18 UTC] [WPMUDEV API Error] 4.1.0 | Connection timed out after 15000 milliseconds ((unknown URL) [500])
[16-Jun-2016 16:30:19 UTC] [WPMUDEV API Error] 4.1.0 | Connection timed out after 15000 milliseconds ((unknown URL) [500])
[26-Jun-2016 04:30:18 UTC] [WPMUDEV API Error] 4.1.0 | Connection timed out after 15000 milliseconds ((unknown URL) [500])

Also saw it in a few other site from time to time.