The rate-limiter seems to be doing its job, to slow down people trying to spam the sign-in page.
However this then shows up as a high-latency alert, e.g. on 2020-06-27:
2:46 AM
Weave CloudAPP Instance: Weave Cloud (prod)
(UsersLatency - WARNING FIRING) default/users: high latency
Impact: Users have a very slow experience logging in
99th percentile latency: 1.650
View firing alerts Playbook Dashboard
containerName: users
description: The users service has a 99th-quantile latency of more than 0.5 seconds for 5m.
The rate-limiter seems to be doing its job, to slow down people trying to spam the sign-in page.
However this then shows up as a high-latency alert, e.g. on 2020-06-27: