Need to know what are the causes so we can avoid it.
Also the corresponding solution if it happens.
Hope you can help.
Below are the posibility of this issue occures:
1. Most of the time because of the Sitelist currupt.
2. Prevent access specific repository (Access block on F/W or any other paremiter)
I have also experienced this error when the DNS settings for the network adapater on the endpoint are not correct (no DNS suffix).