If you try using NTA of Japan’s eTax, are an English speaker, and get this spinning dial forever:
You can hit F12 and you will see an error in the log like this:
Failed to load resource: the server responded with a status of 404 (Not Found)
d._getText @ dojo.js:16
maskat.js:1 Uncaught Error: Could not load ‘dojo.nls.etaxweb_dlparts_en-us’; last tried ‘./nls/etaxweb_dlparts_en-us.js’
at dojo._loadModule.dojo.require (dojo.js:16:5872)
at eval (eval at load (plugin.js:1:15424), <anonymous>:16:66173)
at dojo.i18n._searchLocalePath (eval at load (plugin.js:1:15424), <anonymous>:16:65920)
at _2d5 (eval at load (plugin.js:1:15424), <anonymous>:16:66068)
at dojo.i18n._preloadLocalizations (eval at load (plugin.js:1:15424), <anonymous>:16:66220)
at eval (eval at load (plugin.js:1:15424), <anonymous>:16:430488)
at B.load (plugin.js:1:15424)
at B.loadPlugin (maskat.js:1:24406)
at B.process (maskat.js:1:23098)
at maskat.js:1:50999
The problem is your preferred browser language is English. You need to change it to Japanese to load it up. Or switch locale with an extension.