TypeError: Cannot read property 'lang' of null

[richardolsson]

https://sentry.io/organizations/zetkin-foundation/issues/2422706801/?referrer=github_plugin

TypeError: Cannot read property 'lang' of null
  File "/var/app/build/app/server/locale.js", line 62, in null.<anonymous>
    let locale = state.user.user.lang || browserLocale;
  File "/var/app/build/app/server/datarouter.js", line 118, in Promise.all.then.catch
    Promise.all(promises).then(() => next()).catch(() => next());
...
(3 additional frame(s) were not displayed)

TypeError: Cannot read property 'lang' of null