The following error appears when try to switch to dedicated IP Address through CP "An error occurred during the Plesk operation" Thus domain in Plesk 8.6.0 and 9.5.4 cannot be switched to dedicated IP Address through PBAS 4.3+ Plesk API error: Request is invalid
The issue is caused by invalid XSD schema file on Plesk Panel server. According to it, at least one node is required for API request to change the IP address (in hosting settings) for domains.
On the Plesk node add minOccurs="0" to the corresponding schema file "plesk_domain.xsd". See of the error from PBAS detailed error report to find out the right directory to the schema file.
# diff /usr/local/psa/admin/htdocs/schemas/rpc/126.96.36.199/plesk_domain.xsd /usr/local/psa/admin/htdocs/schemas/rpc/188.8.131.52/plesk_domain.xsd.bak 330c330 < <xs:element name="property" type="PleskPhysHOstingPropertyType" minOccurs="0" maxOccurs="unbounded"/> --- > <xs:element name="property" type="PleskPhysHOstingPropertyType" maxOccurs="unbounded"/>