Hi,
This is not a configuration issue , it’s a bug in PrestaShop 9.0.2.
Your screenshot shows this error:
AddStateCommand::__construct(): Argument #1 ($countryId) must be of type int, string given
So when you save a State, the form sends country_id as a string, but the command expects an int, and the back office crashes.
The real fix :
Update PrestaShop to the latest 9.0.x patch (9.0.3 / 9.0.4+). This issue is typically fixed in a patch release.
Quick workaround (if you can’t update right now)
Patch the core to cast the country id to int in:
src/Core/Form/IdentifiableObject/DataHandler/StateFormDataHandler.php
Before creating the command, cast it:
$countryId = (int) $data['country_id'];
Then use $countryId when building AddStateCommand.
Note: this is a core change and will be overwritten by the next update, so upgrading is the clean solution.
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