Unable to login in QNAP NAS even after soft reset

Hi all,

I had changed router and unable to login to my QNAP thereafter.
I had tried soft reset (hold reset button for 3 sec) but unable to login in with default username: admin and default password: admin.

My QNAP model is TS-228A and version is 5.1.9.2954.

Any kind soul can help me?

with 5.1.x admin/admin is not the default password anymore