diff --git a/datachannel.go b/datachannel.go
index 52de821b7e5..ea50a031feb 100644
--- a/datachannel.go
+++ b/datachannel.go
@@ -464,10 +464,12 @@ func (d *DataChannel) DetachWithDeadline() (datachannel.ReadWriteCloserDeadliner
 	d.mu.Lock()
 
 	if !d.api.settingEngine.detach.DataChannels {
+		d.mu.Unlock()
 		return nil, errDetachNotEnabled
 	}
 
 	if d.dataChannel == nil {
+		d.mu.Unlock()
 		return nil, errDetachBeforeOpened
 	}