Hi, 
We updated SandBox according with production instance, but after that our API integration
with SANDBOX, stop to work.

- We tried so hard looking forums, and websites to help me with this problem but I did not find a solution.

- We imported the WSDL on SOAPui and everything work fine, but when we try to connect via API, we receive that message:

Error Type Detail: SOAP-FAULT-DETAIL
Serialized SOAP fault detail: <detailxmlns:sf="urn:fault.enterprise.soap.sforce.com"
xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <sf:UnexpectedErrorFault
xsi:type="sf:UnexpectedErrorFault">
        <sf:exceptionCode>INVALID_SESSION_ID</sf:exceptionCode>
        <sf:exceptionMessage>Invalid Session ID found in SessionHeader:
Illegal Session</sf:exceptionMessage>
    </sf:UnexpectedErrorFault>
</detail>upSert

Hi, 
We updated SandBox according with production instance, but after that our API integration
with SANDBOX, stop to work.

- We tried so hard looking forums, and websites to help me with this problem but I did not find a solution.

- We imported the WSDL on SOAPui and everything work fine, but when we try to connect via API, we receive that message:

Error Type Detail: SOAP-FAULT-DETAIL
Serialized SOAP fault detail: <detailxmlns:sf="urn:fault.enterprise.soap.sforce.com"
xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <sf:UnexpectedErrorFault
xsi:type="sf:UnexpectedErrorFault">
        <sf:exceptionCode>INVALID_SESSION_ID</sf:exceptionCode>
        <sf:exceptionMessage>Invalid Session ID found in SessionHeader:
Illegal Session</sf:exceptionMessage>
    </sf:UnexpectedErrorFault>
</detail>upSert