TypeError: /app/www/views/layouts/base.ejs:3
   1| <!doctype html>
   2|
>> 3| <html lang="<%- locals.locale.substring(0, 2) %>">
   4|
   5| <head>
   6|     <meta charset="UTF-8">

Cannot read properties of undefined (reading 'substring')
   at eval ("/app/www/views/layouts/base.ejs":12:31)
   at base (/app/node_modules/ejs/lib/ejs.js:703:17)
   at tryHandleCache (/app/node_modules/ejs/lib/ejs.js:274:36)
   at exports.renderFile [as engine] (/app/node_modules/ejs/lib/ejs.js:491:10)
   at View.render (/app/node_modules/express/lib/view.js:135:8)
   at tryRender (/app/node_modules/express/lib/application.js:657:10)
   at Function.render (/app/node_modules/express/lib/application.js:609:3)
   at ServerResponse.render (/app/node_modules/express/lib/response.js:1039:7)
   at /app/node_modules/express-ejs-layouts/lib/express-layouts.js:113:20
   at tryHandleCache (/app/node_modules/ejs/lib/ejs.js:280:5)
   at exports.renderFile [as engine] (/app/node_modules/ejs/lib/ejs.js:491:10)
   at View.render (/app/node_modules/express/lib/view.js:135:8)
   at tryRender (/app/node_modules/express/lib/application.js:657:10)
   at Function.render (/app/node_modules/express/lib/application.js:609:3)
   at ServerResponse.render (/app/node_modules/express/lib/response.js:1039:7)
   at res.render (/app/node_modules/express-ejs-layouts/lib/express-layouts.js:77:18)