I continue to have same issue too, despite clean ubuntu, decent memory, good internet connection, upgraded to beta 2 and still same message. Getting this for 3 days now after trying it many times and leaving it to mine. Thanks.
That’s great! I did the same yesterday and getting the same message as you do - testnet… Nothing in account balance so far after around 24 hours of running, but one of the posts on this forum says that it could take a few days for the first coin (or fraction thereof) to show up in wallet balance…fingers crossed. One more thing (for the avoidance of doubt please): even after deleting testnet3 and freshly installing beta2, a testnet3 folder still shows up in the .zcashconf file - is that normal? Thanks.