I am using trial Splunk cloud instance. When I reboot it is not coming backup giving error"Oops! your instance is no longer here."
Main reason is that as document share by Splunk Guide I have done all necessary configuration for Universal forwarder installation, but my server was not available in Forwarder Management. I try to ping but nothing was working. On client side giving error deployment client not able to communicate with deployment server. So I restart to check may be restarting of splunk cloud server can work.
Are you accessing proper url came to your mail id?
I don't know but doc says this feature is not available for trial, still chek with splunk support.