I have a simmilar problem like the one described here. I made the SD card with Etcher, following all the steps. The Raspberry does start with also a lot of errors. It does suggest me to visit the OMV site, and gives the option to enter the Raspberry Pi by entering username and password. besides that it gives the IP number. The IP number is correct, also in the router, but it does not allow me to enter into the Raspberry (Also not with the default username and password). I have been waiting for over 1 hour, which should be long enough, but the Raspberry didn't reboot, nothing has changed. Also there is no OMV login screen.