ORA-00955 Erorr

Im trying to make migration from visual Studio. Im building a project with Razor pages ASP.NET Core With Oracle database and when i make the migration comes this error:

2020-03-17 22:32:15.351073 ThreadID:1   (ERROR)   OracleRelationalCommand.Execute() :  Oracle.ManagedDataAccess.Client.OracleException (0x80004005): ORA-00955: Es gibt bereits ein Objekt mit diesem Namen
   at OracleInternal.ServiceObjects.OracleConnectionImpl.VerifyExecution(Int32& cursorId, Boolean bThrowArrayBindRelatedErrors, SqlStatementType sqlStatementType, Int32 arrayBindCount, OracleException& exceptionForArrayBindDML, Boolean& hasMoreRowsInDB, Boolean bFirstIterationDone)
   at OracleInternal.ServiceObjects.OracleCommandImpl.ExecuteNonQuery(String commandText, OracleParameterCollection paramColl, CommandType commandType, OracleConnectionImpl connectionImpl, Int32 longFetchSize, Int64 clientInitialLOBFS, OracleDependencyImpl orclDependencyImpl, Int64[]& scnFromExecution, OracleParameterCollection& bindByPositionParamColl, Boolean& bBindParamPresent, OracleException& exceptionForArrayBindDML, OracleConnection connection, OracleLogicalTransaction& oracleLogicalTransaction, Boolean isFromEF)
   at Oracle.ManagedDataAccess.Client.OracleCommand.ExecuteNonQuery()
   at Oracle.EntityFrameworkCore.Storage.Internal.OracleRelationalCommandBuilderFactory.OracleRelationalCommandBuilder.OracleRelationalCommand.Execute(IRelationalConnection connection, DbCommandMethod executeMethod, IReadOnlyDictionary`2 parameterValues)