Are.na unauthorized errors for private channels aren't handled

[dblock]

W, [2022-01-07T17:00:43.505740 #195]  WARN -- : Error getting channel 986556: 401: Unauthorized - Invalid credentials.
W, [2022-01-07T17:00:43.505876 #195]  WARN -- : Error in cron for team name=..., id=..., 401: Unauthorized - Invalid credentials., /app/vendor/bundle/ruby/2.6.0/gems/arena-0.1.3/lib/arena/client.rb:53:in `request'
/app/vendor/bundle/ruby/2.6.0/gems/arena-0.1.3/lib/arena/client.rb:25:in `block (2 levels) in <class:Client>'
/app/vendor/bundle/ruby/2.6.0/gems/arena-0.1.3/lib/arena/api.rb:121:in `object_from_response'
/app/vendor/bundle/ruby/2.6.0/gems/arena-0.1.3/lib/arena/api.rb:21:in `channel'
/app/config/initializers/arena.rb:6:in `try_channel'
/app/vendor/bundle/ruby/2.6.0/gems/arena-0.1.3/lib/arena.rb:26:in `method_missing'
/app/slack-arena/models/arena_channel.rb:3:in `parent'
/app/slack-arena/models/arena_feed.rb:51:in `sync_new_arena_items!'
/app/vendor/bundle/ruby/2.6.0/gems/mongoid-7.1.2/lib/mongoid/association/referenced/has_many/proxy.rb:165:in `block in each'
/app/vendor/bundle/ruby/2.6.0/gems/mongoid-7.1.2/lib/mongoid/association/referenced/has_many/enumerable.rb:193:in `block in each'
/app/vendor/bundle/ruby/2.6.0/gems/mongoid-7.1.2/lib/mongoid/contextual/mongo.rb:710:in `yield_document'
/app/vendor/bundle/ruby/2.6.0/gems/mongoid-7.1.2/lib/mongoid/contextual/mongo.rb:137:in `block in each'
/app/vendor/bundle/ruby/2.6.0/gems/mongo-2.13.0/lib/mongo/collection/view/iterable.rb:51:in `block in each'
/app/vendor/bundle/ruby/2.6.0/gems/mongo-2.13.0/lib/mongo/cursor.rb:163:in `block in each'
/app/vendor/bundle/ruby/2.6.0/gems/mongo-2.13.0/lib/mongo/cursor.rb:161:in `loop'
/app/vendor/bundle/ruby/2.6.0/gems/mongo-2.13.0/lib/mongo/cursor.rb:161:in `each'
/app/vendor/bundle/ruby/2.6.0/gems/mongo-2.13.0/lib/mongo/collection/view/iterable.rb:50:in `each'
/app/vendor/bundle/ruby/2.6.0/gems/mongoid-7.1.2/lib/mongoid/query_cache.rb:228:in `each'
/app/vendor/bundle/ruby/2.6.0/gems/mongoid-7.1.2/lib/mongoid/contextual/mongo.rb:136:in `each'
/app/vendor/ruby-2.6.5/lib/ruby/2.6.0/forwardable.rb:230:in `each'
/app/vendor/bundle/ruby/2.6.0/gems/mongoid-7.1.2/lib/mongoid/association/referenced/has_many/enumerable.rb:189:in `each'
/app/vendor/bundle/ruby/2.6.0/gems/mongoid-7.1.2/lib/mongoid/association/referenced/has_many/proxy.rb:165:in `each'
/app/slack-arena/app.rb:79:in `block in sync!'
/app/vendor/bundle/ruby/2.6.0/gems/mongoid-7.1.2/lib/mongoid/contextual/mongo.rb:710:in `yield_document'
/app/vendor/bundle/ruby/2.6.0/gems/mongoid-7.1.2/lib/mongoid/contextual/mongo.rb:137:in `block in each'
/app/vendor/bundle/ruby/2.6.0/gems/mongo-2.13.0/lib/mongo/collection/view/iterable.rb:51:in `block in each'
/app/vendor/bundle/ruby/2.6.0/gems/mongo-2.13.0/lib/mongo/cursor.rb:163:in `block in each'
/app/vendor/bundle/ruby/2.6.0/gems/mongo-2.13.0/lib/mongo/cursor.rb:161:in `loop'
/app/vendor/bundle/ruby/2.6.0/gems/mongo-2.13.0/lib/mongo/cursor.rb:161:in `each'
/app/vendor/bundle/ruby/2.6.0/gems/mongo-2.13.0/lib/mongo/collection/view/iterable.rb:50:in `each'
/app/vendor/bundle/ruby/2.6.0/gems/mongoid-7.1.2/lib/mongoid/query_cache.rb:228:in `each'
/app/vendor/bundle/ruby/2.6.0/gems/mongoid-7.1.2/lib/mongoid/contextual/mongo.rb:136:in `each'
/app/vendor/ruby-2.6.5/lib/ruby/2.6.0/forwardable.rb:230:in `each'
/app/slack-arena/app.rb:76:in `sync!'
/app/slack-arena/app.rb:12:in `block (2 levels) in after_start!'
/app/slack-arena/app.rb:41:in `block (2 levels) in continuously'
/app/slack-arena/app.rb:40:in `loop'
/app/slack-arena/app.rb:40:in `block in continuously'
/app/vendor/bundle/ruby/2.6.0/gems/async-1.26.2/lib/async/task.rb:258:in `block in make_fiber'.