diff --git a/azure-pipelines.yml b/azure-pipelines.yml
index 42aabf31..e64b1343 100644
--- a/azure-pipelines.yml
+++ b/azure-pipelines.yml
@@ -1,5 +1,5 @@
 pool:
-  vmImage: [ 'ubuntu-16.04', 'ubuntu-18.04' ]
+  vmImage: 'ubuntu-16.04'
 
 jobs:
   - job: Linux1