diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 6f7fbee..78e1b9b 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -16,7 +16,7 @@ jobs:
     strategy:
       matrix:
         otp_version: ['24', '23', '22', '21']
-        os: [ubuntu-latest]
+        os: [ubuntu-20.04]
 
     steps:
     - uses: actions/checkout@v2