Use EF 6.0 SaveChanges() function causes error "Could not load file or assembly " oracle. manageddataaccessdtc, version=4.122.19.1"

I use Oracle.ManagedDataAccess nuget packet, I publish the project to IIS, everything it ok, but if I call the EF function SaveChanges(), I get this error:

Could not load file or assembly Oracle.ManagedDataAccessDTC, Version=4.122.19.1, Culture=neutral, PublicKeyToken=89b483f429c47342 Or one of its dependencies,Find the assembly manifest definition does not match the assembly reference. ( exception from hresult:0x80131040 )

I put the Oracle.ManagedDataAccessDTC.dll in the publish folder in the bin directory, but I still get the error.

Please give me some advice! Thanks!