diff --git a/retrieval/target.go b/retrieval/target.go
index f0045963d..2d5d4e282 100644
--- a/retrieval/target.go
+++ b/retrieval/target.go
@@ -227,7 +227,7 @@ func (t *target) StopScraper() {
 	t.stopScraper <- true
 }
 
-const acceptHeader = `application/vnd.google.protobuf;proto=io.prometheus.client.MetricFamily;encoding=delimited;q=0.7,text/plain;version=0.0.4;q=0.3,application/json;schema=prometheus/telemetry;version=0.0.2;q=0.2,*/*;q=0.1`
+const acceptHeader = `application/vnd.google.protobuf;proto=io.prometheus.client.MetricFamily;encoding=delimited;q=0.7,text/plain;version=0.0.4;q=0.3,application/json;schema="prometheus/telemetry";version=0.0.2;q=0.2,*/*;q=0.1`
 
 func (t *target) scrape(ingester extraction.Ingester) (err error) {
 	timestamp := clientmodel.Now()