The Salesloft Cadence error "unable to send email via gateway" means Salesloft can't authenticate or relay your outbound message through your connected email provider (Gmail, Outlook/Microsoft 365, or SMTP). Fix it by reconnecting your email account, re-authorizing OAuth permissions, and confirming your provider isn't blocking third-party sends. Most cases resolve in under five minutes with a reconnect.

What the error actually means

Salesloft doesn't send email from its own servers. It relays messages through your mailbox using a gateway — either OAuth (Gmail/Microsoft) or SMTP/IMAP credentials. When you see "unable to send email via gateway," the handshake between Salesloft and that mailbox failed. The message never left your outbox.

Most teams assume it's a Salesloft bug. It usually isn't. Nine times out of ten it's an expired token, a revoked permission, or a security policy on the email provider side.

Diagram showing Salesloft relaying an email through a user mailbox gateway via OAuth to Gmail and Microsoft 365, with a broken connection highlighted in red

Step-by-step fixes

1. Reconnect your email account

This clears the most common cause: a stale OAuth token.

  1. In Salesloft, click your profile icon and open Settings.
  2. Go to My Settings → Email Connection (or Personal Settings in older UIs).
  3. Click Disconnect, then Connect again.
  4. Sign in through your provider and approve every permission prompt — don't skip the send/compose scope.

After reconnecting, send a test email from a live Cadence step. If it goes out, you're done.

2. Re-authorize OAuth scopes

Admins sometimes tighten Google Workspace or Microsoft 365 app permissions, which silently revokes Salesloft's send access. If the reconnect above throws a permissions error:

  • Google Workspace: Ask your admin to confirm Salesloft is allowed under Security → API Controls → App Access Control. Google's own guidance on managing third-party app access walks through allowlisting.
  • Microsoft 365: Check that Salesloft isn't blocked in Microsoft Entra ID → Enterprise Applications. Conditional Access policies or MFA changes are frequent culprits.

3. Check SMTP/IMAP credentials (non-OAuth setups)

If you connect via SMTP instead of OAuth, an app password or port setting is likely wrong. Verify:

SettingCommon correct value
SMTP hostsmtp.office365.com / smtp.gmail.com
SMTP port587 (TLS) or 465 (SSL)
UsernameFull email address
PasswordApp password, not your login password
EncryptionSTARTTLS / SSL enabled

Gmail and Microsoft both now require an app-specific password when 2FA is on. A regular password will fail the gateway every time.

4. Clear provider-side send blocks

Even with valid auth, your provider can reject the relay:

  • Sending limits hit — Google caps ~2,000 messages/day, Microsoft ~10,000 recipients/day. Blowing past these returns a gateway failure until the window resets.
  • Suspended or flagged mailbox — a spam trip or compromised-account lock stops all third-party sends.
  • DNS/SPF/DKIM misconfig — if outbound authentication records are broken, some providers refuse the relay. Confirm your SPF and DKIM records are valid.

Generate Proposals with AI in seconds.

Try now
Proposal album preview

Still failing? Escalate correctly

If reconnecting and permissions are clean, capture the exact error text and timestamp, then open a ticket with Salesloft Support. Include whether the failure hits one user or the whole team — a team-wide outage usually points to an admin-level Workspace/Entra policy, not an individual token.

Keep a short internal runbook for this. Teams focused on improving pipeline velocity can't afford reps blocked mid-cadence, and a documented reconnect flow turns a 30-minute panic into a two-minute fix.

Preventing repeat gateway errors

Tokens expire, and password rotations break SMTP connections. A few habits cut recurrence:

  • Reconnect email after any password change or MFA reset.
  • Have admins whitelist Salesloft before rolling out new Conditional Access or API controls.
  • Monitor daily send volume so reps don't silently hit provider caps.

If your team is rethinking the broader tooling picture — for example planning a migration from Salesloft Rhythm to a custom AI GTM stack — audit these email-gateway dependencies early, since OAuth relays behave the same across most sequencing platforms.

Screenshot-style illustration of a Salesloft email connection settings page showing a green connected status after reconnecting the mailbox

Key takeaways

  • "Unable to send email via gateway" means Salesloft couldn't relay through your mailbox — the mail never sent.
  • Reconnecting your email account fixes the majority of cases by refreshing the OAuth token.
  • OAuth scope revocations and Conditional Access changes are the top admin-side causes.
  • SMTP setups usually break because of a missing app password or wrong port (587/465).
  • Watch daily send limits and reconnect after every password or MFA change to prevent repeats.