diff --git a/client/grpc/error.go b/client/grpc/error.go
index 1cd36842..8088c552 100644
--- a/client/grpc/error.go
+++ b/client/grpc/error.go
@@ -24,7 +24,9 @@ func microError(err error) error {
 
 	// return first error from details
 	if details := s.Details(); len(details) > 0 {
-		return microError(details[0].(error))
+		if verr, ok := details[0].(error); ok {
+			return microError(verr)
+		}
 	}
 
 	// try to decode micro *errors.Error