Could you try these steps, may be it could help solve your problem. Click on your profile picture > account > professional hosting tool > manage > click on use professional tools. Disregard this steps if you already have it turned on.
Next go to your calendar. Click on host > calendar > highlight the dates the appears as blocked on the guest, then set the rule-sets to none on the right side menu. After this, just repeat the steps above then click stop using them on the professional tools to turn it off. Btw, it should say setting instead of account.