Devise

The NoDatabaseError in Devise usually occurs when database migrations haven't been run, and thus the required tables are missing. Resolve this by running `rails db:create` followed by `rails db:migrate` to create and populate the database with the necessary tables for Devise. If the database already exists, ensure it's accessible and that your database.yml configuration is correct.

BackgroundJobError in Devise often arises from `deliver_later` calls within Devise mailers failing due to transaction issues during testing or inconsistent configurations. To fix this, configure your test environment to use `deliver_now` for Devise emails by setting `config.action_mailer.delivery_method = :test` and `config.action_mailer.perform_deliveries = true` in `config/environments/test.rb`, or ensure asynchronous delivery mechanisms are properly set up and reliable in all environments. Examine Devise initializers for potentially incorrect configurations.

The ActiveRecord::ReadOnlyError in Devise usually occurs when attempting to modify user attributes during sign-in or other database operations on a read-only database connection or replica. To fix this, ensure Devise operations (especially writes) are performed on the primary, writable database. Configure your application to route Devise's database writes to the appropriate connection using `ActiveRecord::Base.connected_to(role: :writing) { ... }` blocks or similar connection management techniques to target the writable database.