After login, I get the home page but nothing on it.
In the public/legacy/suitecrm.log, the only error is this:
[103][1][FATAL] Exception handling in /app/suitecrm/public/legacy/include/MVC/Controller/SugarController.php:397
[103][1][FATAL] Exception in Controller: No module defined
Migration was successful, but I could not login → In the database, I changed the id of the admin user to 1 (from this post)
It worked immediately after this.
Maybe it solves the login problem but messes things up in other ways? Permissions?
I updated from 8.61 to 8.7-beta and had same problem. disabled the line as you indicated and it works now and I can see the emails in my Timeline with Contacts. Previously, the email page was blank. Good sleuthing and repair suggestion on Github.