Errors in console when loading web UI

[cwBrendan]

I have Mailsac setup on an Ubuntu server. When I load the web UI in a browser I receive a number of errors in the console. I also receive similar errors when I attempt to check an email (which does not work). Here is the error:

Error: Can't set headers after they are sent. at ServerResponse.OutgoingMessage.setHeader (_http_outgoing.js:335:11) at ServerResponse.header (/opt/mailsac/node_modules/express/lib/response.js:718:10) at ServerResponse.send (/opt/mailsac/node_modules/express/lib/response.js:163:12) at done (/opt/mailsac/node_modules/express/lib/response.js:957:10) at Object.exports.renderFile (/opt/mailsac/node_modules/jade/lib/index.js:374:12) at View.exports.__express [as engine] (/opt/mailsac/node_modules/jade/lib/index.js:417:11) at View.render (/opt/mailsac/node_modules/express/lib/view.js:126:8) at tryRender (/opt/mailsac/node_modules/express/lib/application.js:639:10) at EventEmitter.render (/opt/mailsac/node_modules/express/lib/application.js:591:3) at ServerResponse.render (/opt/mailsac/node_modules/express/lib/response.js:961:7) at exports.errorHandler (/opt/mailsac/lib/middleware.js:102:13) at Layer.handle_error (/opt/mailsac/node_modules/express/lib/router/layer.js:71:5) at trim_prefix (/opt/mailsac/node_modules/express/lib/router/index.js:310:13) at /opt/mailsac/node_modules/express/lib/router/index.js:280:7 at Function.process_params (/opt/mailsac/node_modules/express/lib/router/index.js:330:12) at next (/opt/mailsac/node_modules/express/lib/router/index.js:271:10)

This started happening a few weeks ago but nothing has changed on our end. Any idea what might be causing this and how to fix it?