diff --git a/execution-environment.yml b/execution-environment.yml
index 823b2ee..3b920ef 100644
--- a/execution-environment.yml
+++ b/execution-environment.yml
@@ -53,6 +53,7 @@ dependencies:
     pyyaml
     six
     receptorctl
+    requests-credssp
 additional_build_steps:
   append_base:
     - RUN $PYCMD -m pip install -U pip