diff --git a/realis.go b/realis.go
index 5b5ee05..fe4c5e8 100644
--- a/realis.go
+++ b/realis.go
@@ -321,7 +321,7 @@ func NewRealisClient(options ...ClientOption) (Realis, error) {
 	config.timeoutms = 10000
 	config.backoff = defaultBackoff
 	config.logger = &LevelLogger{logger: log.New(os.Stdout, "realis: ", log.Ltime|log.Ldate|log.LUTC)}
-	config.certExtensions = map[string]struct{}{"crt": {}, "pem": {}, "key": {}}
+	config.certExtensions = map[string]struct{}{".crt": {}, ".pem": {}, ".key": {}}
 
 	// Save options to recreate client if a connection error happens
 	config.options = options
diff --git a/util_test.go b/util_test.go
index 1b374a3..f177bbf 100644
--- a/util_test.go
+++ b/util_test.go
@@ -102,7 +102,7 @@ func TestCurrentBatchCalculator(t *testing.T) {
 }
 
 func TestCertPoolCreator(t *testing.T) {
-	extensions := map[string]struct{}{"key": {}, "pem": {}, "crt": {}}
+	extensions := map[string]struct{}{".pem": {}}
 
 	_, err := createCertPool("examples/certs", extensions)
 	assert.NoError(t, err)