Receive error when open Java GUI

[T_N]

Hi All;

I receive error " Unable to obtain display for Robot, Error: java.lang.NullPointerException"  when I opn Robot from Media Device Management. Anyone has idea on it? Thank you.

TN

[PatS729]

Looks like the robot lost connectivity with the Master/Media server. Try to fix connectivity issues between robot and Master/media.

You may like to try one of the resolution/troubleshooting steps from this article : https://www.veritas.com/support/en_US/article.TECH169477

[T_N]

but if I close/reopen GUI, it works well. it happens often. Any idea why? What log should I check, thank you.