Hi cybekal,
The following steps address what you're describing specifically, and should provide a solution:
Automate accessories at a certain time
Create an automation that runs at a specific time, on certain days, and based on who’s home.
1. In the Home app, tap or click the Add button
, then select Add Automation
.
2. Choose A Time of Day Occurs, then choose a time and day. Tap or click People to have the automation occur at a certain time when someone is home. Tap or click Next.
3. Select scenes and accessories to automate, then tap or click Next.
4. To adjust an accessory on iPhone or iPad, touch and hold it. On Mac, click the accessory. To preview the automation, tap or click Test This Automation.
5. Tap or click Done.
You can find these steps along with other information that may be helpful, here: Create scenes and automations with the Home app - Apple Support
If you have followed the steps correctly and you still have the issue, let us know if you get any specific alerts or error messages when trying, as those may help us determine what might be causing the issue.
We also recommend restarting your device and keeping it updated as those steps assure you have cleared out any minor software issues and are running the most current version. Also check for any firmware updates for the smart plugs. You may have to contact the manufacturer for guidance with that.
Restart your iPhone - Apple Support
Update your iPhone or iPad - Apple Support
If you still have questions, reach out to Apple Support directly, as this may require closer guidance: Get Support
Cheers!