When you are getting the message
You are currently not allowed to log in because you had too many failed logins, try again later. it is because the Matomo brute force detection was triggered.
You can workaround this issue by whitelisting your IP address in Matomo > Administration > General Settings > Login, under the setting called “Never block these IPs from logging in”. If you enter your IP address in this field and then click Save, this will disable the brute force detector feature, and you shouldn’t get the error message “you are currently not allowed to log in” anymore.
For reference, here is what the Login settings look like: