diff --git a/tox.ini b/tox.ini
index f55e297488a729a9bb95b370ff7c4980801e1909..c1999865264daa3615c48640f63a9e4be0c924cb 100644
--- a/tox.ini
+++ b/tox.ini
@@ -15,6 +15,7 @@ setenv =
     PYTHONPATH = {toxinidir}
 passenv =
     DISPLAY
+    XAUTHORITY
 ; HTTP_PROXY+HTTPS_PROXY required behind corporate proxies
     HTTP_PROXY
     HTTPS_PROXY
@@ -29,7 +30,12 @@ ignore = E121 E126 E123 E128 E133 E226 E241 E242 E704 W291 W293 W391 W503 W504 W
 
 [testenv:flake8]
 basepython = python
-passenv = DISPLAY
+passenv =
+    DISPLAY
+    XAUTHORITY
+; HTTP_PROXY+HTTPS_PROXY required behind corporate proxies
+    HTTP_PROXY
+    HTTPS_PROXY
 deps =
     -r{toxinidir}/requirements_torch_training.txt
 commands =