Static Embed Dashboard inside another Dashboard

I have created two dashboards (e.g. Dashboard A & Dashboard B) in the Metabase. Both are working fine individually.

However, we need to consolidate into only one dashboard. So our approach is to add Dashboard B into Dashboard A's tab using iframe.

However, I got Token is missing valuye for keypath: [:_embedding_params] as below:

Both dashboards have the same domain name e.g. sandbox.abc.com.

this will only work with public links, not static embedding. You need to build a backend for static embedding to work