a) Try different networks and RDP clients
b) See if there are error messages in the
Serial Console of the servers.
c) Keep a log to try to determine patterns on times, servers and locations when this happens.
d) Use
ICMP and
traceroute to gain visibility over the network
e) You could spin a linux VM in your project, install
telnet and test connectivity to the RDP port (i.e. telnet x.y.z.w 3389) when you are experiencing the issue. That would also help you discard a network problem.
f) Check utilization resources in your servers when this happens Cloud Console-> Server (i.e. CPU, memory).
g) Follow
this Microsoft troubleshooting guide and check this
discussion.
h) Turn on some
RDP auditing in your servers to add visibility
Since there are many components involved and your problem is intermittent it might take some effort to isolate the problem.