diff --git a/Jenkinsfile b/Jenkinsfile
index 42619e0..454b119 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -557,7 +557,7 @@ pipeline {
 									 """.stripMargin())
 									}
                        if((_GIT_BRANCH=="master") && (bPushMasterOnPypi)) {
-                           withCredentials([string( credentialsId: _PypiCredentials, passwordVariable: 'PYPI_PASSWORD', usernameVariable: 'PYPI_USERNAME')]) {
+                           withCredentials([usernamePassword( credentialsId: _PypiCredentials, passwordVariable: 'PYPI_PASSWORD', usernameVariable: 'PYPI_USERNAME')]) {
                             sh(script:   """#!/bin/sh -
                                             |. ~/TOOLS_ENV/bin/activate
                                             |exec twine twine upload -r ${PY_PROJECT_NAME} dist/* -u ${PYPI_USERNAME} -p ${PYPI_PASSWORD} --non-interactive --disable-progress-bar