@masakichi 

You're sure it was working fine before you upgraded the firmware right?
Did you change any configurations before the problem occurred?
Maybe you could post a picture of the problem?Is it a Zoom web version or an app or something?

Is Zoom the only one that can't be accessed?

  @Md-Ripon3 

Yes.
I was able to access Zoom fine before the update.

After the first update, I could no longer access Zoom, so I checked the Deco app and it looked like I could update the firmware further, so I updated to 1.7.3.

After updating to 1.7.3, the symptoms continue.

Both web and app versions cannot connect.

Only Zoom is confirmed to be unable to connect at this time.

  @Md-Ripon3 

After updating the firmware, I updated macOS (14.0 Sonoma) too, before connecting to Zoom.

  @Md-Ripon3 

The cause was that after a firmware update, the MTU setting value was set to the default value of `1480`.

By changing the MTU value to `1454`, which is the default value when using PPPoE with FLET'S Hikari in Japan, the problem of not being able to connect to Zoom was resolved.

Thanks.