diff --git a/devops-stages/stage-test.sh b/devops-stages/stage-test.sh
index bfcdf9bde9e9330669be31b35a095067bf13a043..23f2dd6893e2fb66c7543f33dc91617dd1a47733 100755
--- a/devops-stages/stage-test.sh
+++ b/devops-stages/stage-test.sh
@@ -14,6 +14,6 @@
 # limitations under the License.
 set -e
 echo "Launching tox"
-tox --parallel=auto
+tox
 
 
diff --git a/releasenotes/notes/single_tox_environment-30aaca72e8b59c4e.yaml b/releasenotes/notes/single_tox_environment-30aaca72e8b59c4e.yaml
new file mode 100644
index 0000000000000000000000000000000000000000..186d4d9d86a35232da02d22611d2a2712da42fbc
--- /dev/null
+++ b/releasenotes/notes/single_tox_environment-30aaca72e8b59c4e.yaml
@@ -0,0 +1,23 @@
+#######################################################################################
+# Copyright ETSI Contributors and Others.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#######################################################################################
+---
+other:
+  - |
+    Running several tox environment parallely causes failures during stage tests frequently.
+    Although the reason is not clear, we are suspicious that environments are affecting each other.
+    This change allows to run only one tox environment at the same time.
+