diff --git a/fpdf.go b/fpdf.go
index 5ff1f45..5ac99dd 100644
--- a/fpdf.go
+++ b/fpdf.go
@@ -3503,7 +3503,7 @@ func (f *Fpdf) getpagesizestr(sizeStr string) (size SizeType) {
 				f.err = fmt.Errorf("unknown page size %s", sizeStr)
 			}
 		}
-		size, ok = SizeType{aFloat[0], aFloat[1]}, true
+		size, ok = SizeType{aFloat[0], aFloat[1]}, false
 	} else {
 		//20210302 archium addendum end
 		size, ok = f.stdPageSizes[sizeStr]