diff --git a/poll/instance.go b/poll/instance.go
index 706e92e..17a2654 100644
--- a/poll/instance.go
+++ b/poll/instance.go
@@ -24,7 +24,9 @@ func PollMastodonPleroma(endpoint string, reportPostChan chan ReportPost) {
 	http_client := http.Client{Timeout: 5 * time.Second}
 
 	for {
+		ri_mutex.Lock()
 		m := runninginstances[endpoint]
+		ri_mutex.Unlock()
 
 		api_timeline := "https://" + endpoint + "/api/v1/timelines/public?limit=40&min_id=" + min_id
 		resp, err := http_client.Get(api_timeline)