Please go to ACR settings and tap on version then tap on Debug and enter letmedebug as password. Make a call while debug is enabled, come back open debug logging and select send to send debug logs to me
Issue seams resolved, rebooted the server/router and reconnected and it did a batch upload of all pending calls,
To be honest I think it might of been an internal issue with the network.
java.net.ConnectException: failed to connect to /172..... (port 21) from /172...... (port 53630) after 10000ms: isConnected failed: ENETUNREACH (Network is unreachable)