This is expected as described in the new changes:
A limit has been applied for scheduling violators, currently is 2 observations per day but it is configurable and it will be re-evaluated in the near future. This limit doesn’t apply for Operators group scheduling.
What the error bellow says is that for the period from 2022-08-18 16:26:26 UTC to 2022-08-20 08:29:28 UTC there are already scheduled observations for this satellite and you can not schedule more. You will be able to schedule after the end of this period if no one else has scheduled.