You can't log in to the HTTPS web interface of TAC with the default credentials, instead you receive the following 500 error below the login form:
Type 'org.talend.gwttoolkit.client.model.LoginResultBean' was not assignable to 'com.google.gwt.user.client.rpc.IsSerializable' and did not have a custom field serializer.For security purposes, this type will not be serialized.
When a web application is updated but the web-browser cache is full, the browser will still use the old files and not update the changes.
Navigate to tac-installation-folder\apache-tomcat\ and clear all contents of the temp and work folders.
Clear the web-browser cache.
Note: this does not always work with the IE browser.