Hi Soichi, 

Welcome to Box Community!

Here are some troubleshooting steps to try:

1. Make sure that the browser is up to date
2. Clear the browsing history
3. Temporary disable plugins/extensions, firewall, and VPN
Use a different browser
4. Check if your firewall is configured for Box apps
5. Try to connect to a different network 
 
I trust that the above steps will do the trick. Let me know how it goes!

Thank you for advice me, Ann.

Here are the results of my checks:

> 1. Make sure that the browser is up to date

I am using Google Chrome version 119.0.6045.160, which is the latest version.

> 2. Clear the browsing history

I deleted all history, cache, and cookies and tried again, but the same problem occurred.

> 3. Temporary disable plugins/extensions, firewall, and VPN

I tried all of these, but the same problem occurred.

> Use a different browser

I performed the same operation on my smartphone, but the same problem occurred.

> 4. Check if your firewall is configured for Box apps

I am not using Box apps. Everything is done on the web.

> 5. Try to connect to a different network 

I switched Wi-Fi networks and tried again, but the same problem occurred.

Could you please create a support ticket, just like the others have done?