Belt slipping on Eurezo Strol 2E

Just received my walking pad. I loosened the belt to lubricate. Used the amount of lubricant recommended. Now, after tightening, the belt shifts quickly to the right without anyone on the pad. I’ve tried tightening but still shifting. I really don’t want to send this back, so hopefully someone has some advice. I tried calling the support number in my manual but kept getting Verizon error messages 😩