Errors and sessions

Error explorer

Errors (/web-experience/errors) groups JavaScript errors and failed requests by signature, with counts, affected users, and the first/last seen. Open a group to see the stack and the sessions that hit it.

Sessions and replays

Sessions (/web-experience/sessions) lists individual visits; open one to reconstruct what the user did — pages, clicks, errors — leading up to a problem.

Cookbook: a spike in checkout errors

Open Errors; sort by recent volume to find the new/spiking group.
Read the stack and the affected page/release.
Open an attached session to watch the exact steps that triggered it.
If it's server-side, jump to the service's traces in Applications.