You tried to install grub to /dev/sdb, and it appears to be partitioned incorrectly. Instead of starting at the 1 MiB mark, the partition starts only 16k into the disk, and this does not leave enough room for grub. Delete the partition and start over.
You tried to install grub to /dev/sdb, and it appears to be partitioned incorrectly. Instead of starting at the 1 MiB mark, the partition starts only 16k into the disk, and this does not leave enough room for grub. Delete the partition and start over.