If you get "Error creating sequencer" (or a similar connection error) when linking Smartlead, Instantly, or another tool, it almost always comes down to one of the causes below. Work through them in order.
1. Check your login details
In Settings → Sequencers, open the Configure step for your tool.
Enter your sequencer's login email and password — not an API key. The Workspace Name, API key, and Consent URL fields are optional.
Double-check for typos or a recently changed password.
2. Turn off two-factor authentication (2FA)
If 2FA is enabled on your Smartlead or Instantly account, it can block the connection and produce this error. Temporarily disable 2FA on the sequencer, connect, and then re-enable it if you wish.
3. Make sure the same sequencer isn't already connected to another Maildoso account
Each sequencer login can normally be actively connected to only one Maildoso account at a time. If you (or a teammate) already connected that same Smartlead or Instantly login to a different Maildoso account, trying to connect it again from a second account can fail with "Error creating sequencer."
Disconnect the sequencer from the other Maildoso account first, then connect it here.
If you no longer have access to that other account and can't disconnect it yourself, contact us and we'll clear the old connection so you can reconnect.
4. Confirm your mailboxes are active
Accounts that are still pending, inactive, or over your current plan's limit can't be added to a sequencer. Make sure the mailboxes show as Active and that your subscription covers all of your mailboxes and domains, then retry.
If you've checked all of the above and it still fails, contact us with the exact error message and the mailboxes involved, and we'll review your specific case and get it working.