SSIS package (through sql script) does not run on local SSMS or in job

Hi,

I'm a newby to SSIS (sql server 2016) and I have an issue with the import of a file. I have a package that run's fine on the server A.

It will load an xls file X on server B and import the file in a database on server A.

This works:

- access remotely SSMS on server A with my windows account: run the package (see below) : ok

- open SSMS locally (on my machine), connect to the server and run the same package: FAILS with message:

"It is already opened exclusively by another user, or you need permission to view and write its data.". 

I'm sure the file is closed. As kind of test, I have copied the file once to server A and than it works (running the same script from my local machine).

Package SQL script (simplified):

--DB on Server A (SSISDB as well)

Declare @intExecution_id bigint
EXEC [SSISDB].[catalog].[create_execution]  'APP','APP_ETL','import.dtsx',NULL,1,@intExecution_id out
--DEFINE PARAMETERS INPUT
EXEC [SSISDB].[catalog].[set_execution_parameter_value]  @intExecution_id,30,'strExcelLoc',"\\serverB\Application Files\"
EXEC [SSISDB].[catalog].[set_execution_parameter_value]  @intExecution_id,30,'strExcelFile',"import.xls"
EXEC [SSISDB].[catalog].[set_execution_parameter_value]  @intExecution_id,30,'strSQLConnection',"xxx"
EXEC [SSISDB].[catalog].[start_execution] @intExecution_id    

I don't know if the problem is related, but when putting this into a job, it always fails. Running the job on the server or remotely.

Anyone an idea ?