If action=query&meta=authmanagerinfo returned true for hasprimarypreservedstate, requests marked as primary-required should be omitted. If it returned a non-empty value for preservedusername, that username must be used for the username parameter.
The database is currently locked to new entries and other modifications, probably for routine database maintenance, after which it will be back to normal.
The system administrator who locked it offered this explanation: Major Server Maintenance, Access wil be restored soon.