DIAGNOSIS: Yeah, this one's common. That grinding or screeching noise is almost always a piece of a spent coffee capsule—usually the aluminum rim—that got left behind and is now jammed in the brewing mechanism.
FIX: Unplug the machine. Open and close the head a few times manually to see if anything falls out into the drip tray. Then, take a good flashlight and look up into the pod holder. You might see a sliver of silver metal stuck to the black puncture needle or wedged in the rim. Use a pair of tweezers or needle-nose pliers to very carefully pull it out. Do not force anything.
IF THAT DIDN'T WORK: The noise could be from the motor or centrifuge mechanism itself starting to fail, especially if there's no visible debris. Try running a cleaning cycle (press the button three times in two seconds) without a pod. If the noise persists without any capsule in there, it's likely an internal mechanical issue.
HEADS UP: Always eject the used pod right after brewing. Letting it sit in the hot, damp chamber can cause the aluminum foil to soften and tear more easily when you finally eject it, leaving bits behind.