diff --git a/files/geant_acme_uploader.py b/files/geant_acme_uploader.py
index 0e154d03c230d69c48aabe06c453fc4062ecc397..6f25db5bbe5d12d4242f1e20a586765d9b31bfd2 100755
--- a/files/geant_acme_uploader.py
+++ b/files/geant_acme_uploader.py
@@ -80,7 +80,7 @@ if __name__ == "__main__":
     for certname in ['cert.pem', 'chain.pem', 'fullchain.pem']:
         with open(os.path.join(BASEDIR, DOMAIN, certname), 'r') as certfile:
             certdata = certfile.read()
-            domain_underscored = DOMAIN.replace('', '_')
+            domain_underscored = DOMAIN.replace('.', '_')
             # let's rename everything to .crt, which is what we normally use
             certname_renamed = certname.replace(
                 'cert.pem', '.crt').replace('chain.pem', 'chain.crt')