It says that The motherboard M.2 slot #1 shares bandwidth with a SATA 6.0 Gb/s port. When the M.2 slot is populated, one SATA 6.0 Gb/s port is disabled.
This is normal. If you install an M.2 SSD, it usually (on most, if not all Z370 motherboards), disables a SATA port or two (depending on the specific mobo). All you have to do is use another SATA port, and the manual will tell you which ports would be disabled.
What mobo are you using? And if it has more than one M.2 slot, which one did you install the M.2 SSD in? Lastly, what specific M.2. drive are you using (so I can check if it's an M.2 SATA or M.2 NVMe drive ... makes a difference).
Please help don’t know what part is making this happen and I’m very confused