Internal Hard drive for 2000 Pro

I've seen a lot of posts online about this issue, but have yet to find a definitive answer. I just purchased a 2000 pro and installed a 16tb Ironwolf Pro drive and it works perfectly via USB 3, but when I install it internally - nothing. I've formatted EXFAT, NTFS etc, but nothing works. Anyone else have a fix for this?

 

Fixed. Had a partition that was not visible in windows disk manager but showed up in aomei.

 

Same issue 16TB Ironwolf Pro not recognized internally on Zidoo Z2000 Pro. Works fine via USB. Tried formatting EXFAT, NTFS.