Fail to decrypt a SSIS package

We have a SSIS package developed by a 3rd-party. When I access the package in Visual Studio using the password of the 3rd -party, everything looks normal.
However, when I log into the Visual Studio using my own user name and password, I can see the package, but data can't be loaded. Below is the error message. Our IT told me that they have given me access to the database, why I'm still having permission issue?

Severity Code Description Project File Line Suppression State
Error Error loading SAP By Design Read Facts.dtsx: Failed to decrypt protected XML node Property with error 0x8009000B Key not valid for use in specified state.. You may not be authorized to access this information. This error occurs when there is a cryptographic error. Verify that the correct key is available.
Error Validation error. Fact_Baseline Days CData SAPByDesign Source: Unable to get the schema of the data source. SAP By Design Read Facts.dtsx 0

There are several ways of security when you save your passwords in SSIS. One is based on a password, the other is username and password. When you open the package and the user name is different you have to change the passwords. You should check the protection level of the package.