@andreasdueren thank you Andreas, it works perfectly.
I think it's different code with the tutorial that come from here https://developers.chatwoot.com/self-hosted/configuration/multi-factor-authentication:
# Active Record Encryption keys (required for MFA/2FA functionality)
# Replace with the actual keys from rails db:encryption:init output
ACTIVE_RECORD_ENCRYPTION_PRIMARY_KEY=EGY8WhulUOXixybod7ZWwMIL68R9o5kC
ACTIVE_RECORD_ENCRYPTION_DETERMINISTIC_KEY=aPA5XyALhf75NNnMzaspW7akTfZp0lPY
ACTIVE_RECORD_ENCRYPTION_KEY_DERIVATION_SALT=xEY0dt6TZcAMg52K7O84wYzkjvbA62Hz
When I tried your code, now it appears on my dashboard:
# Active Record Encryption keys (required for MFA/2FA functionality)
# Replace with the actual keys from rails db:encryption:init output
export ACTIVE_RECORD_ENCRYPTION_PRIMARY_KEY=string
export ACTIVE_RECORD_ENCRYPTION_DETERMINISTIC_KEY=string
export ACTIVE_RECORD_ENCRYPTION_KEY_DERIVATION_SALT=string
Now, I can see the 2FA option.
Thank you...

