Metabase Slack setup

Trying to setup the Slack Metabase integration but keep getting the error:

Public channel to store image files: channel not found

I created the Slack app, installed it in the Slack workspace. Created the public channel in Slack. Added the Metabase app to the Slack channel. Copied and pasted the Slack Bot User OAuth Token from Slack app to Metabase. Tried with the channel name metabase_files and also the channel ID from Slack. Both have the same error. Any ideas?

Bot Token Scopes:
channels:join
channels:read
chat:write
chat:write.customize
chat:write.public
files:write
users:read Scope