Try taking the lock nut off and taking the arms apart, give them a clean, grease the pivot points and put back together.
If you don’t want to take apart put some spray lube in the pivot point and work it a bit.
Also try undo the bolt holding it to the frame hold the brake hard against the rim and then do up again to try relocating it. That can often work. In fact try that first then try cleaning it up. It might just be fitted a bit too much to one side of the rim.
Try taking the lock nut off and taking the arms apart, give them a clean, grease the pivot points and put back together.
If you don’t want to take apart put some spray lube in the pivot point and work it a bit.
Also try undo the bolt holding it to the frame hold the brake hard against the rim and then do up again to try relocating it. That can often work. In fact try that first then try cleaning it up. It might just be fitted a bit too much to one side of the rim.