Carbon Copy Cloner on 10.14.5 Cloned External Hard Drive not booting

Hello community! Anyone can shed help? I have tried cloning a 2017 non T2 chip Macbook Pro to an external hard drive. I cleaned the external hard drive using DISKPART on windows so when I plug it to the Mac it will initialize and give the options for APFS and GUID... the cloning went well but after finishing and booting on to the external hard drive, the EHD is not being mounted or read at start up. But when I live it plugged in, and start on the internal hard drive of the mac, the EHD is mounted and can be accessed.

Thanks much!