Yes report server is up and functional, as well as CRM. When one of the two CRM server is down, reports work, showing that services are well up and running.
I am now looking at errors that may be linked such as "Lost contact with a Sandbox client" and eventid 20246 for this process.
Will open new thread for that purpose. Report Server seems not the root cause but the the Sandbox <-> Asynch
Thanks for your input
Regards
/Patrice