MMDVM unable to access from web and SSH

[9V1YW]

One of my Pi Zero W now have this problem:
Cannot access from both webpage of SSH. However, all other functions work well such as internet connection, receive and transmit.

I further tried a few methods listed below and all cannot work, the problem is still existing.
burn a new TF card image (same problem);
use another card from my other pi zero w which is perfectly working (same problem);
put this TF card into other pi zero w, but it works perfectly well;

It looks like software issue, but why all the cards works perfectly well on the other pi zero w but it just does not work on my own pi zero w (webpage and SSH). Is it possible to be hardware issue for my pi zero w?

[AF6VN]

Are both units powered and connected to the same router, at the same time? If so, you may be having conflicts due to hostname being the same.