On DomainsExtensionScreen, while putting a domain into basket, the errors appears on the next screen:
Parameter Validation Error: Contact type
Error validating parameters Registrant Type:
Online Store might be using some customized layout templates, but the issue persists after resetting customization to default.
Issue is caused by one of the advanced settings of the Online Store:
BA Providers Control Panel > Home > Products > Online Store > Advanced Settings >
PERIOD_PRICE_CALC_TYPE is set to non-default value (auto)
The error raises while Online Store tries to use different Plan Period calculation algorithm using yet not-entered service parameters.
Issue was confirmed as product bug with id PBA-34474 ("Store. Immediate error when checking provisioning parameters when PERIOD_PRICE_CALC_TYPE is set to "auto").
Set PERIOD_PRICE_CALC_TYPE to default "False" value.
Issue will be fixed in one of the future product updates.