- Your normal Google password will NOT work. Google blocks SMTP sign-in with your account password — you must paste a 16-character App Password (requires 2-Step Verification on the account, and your Workspace admin must allow App Passwords). This is a Google rule, not an Inflowave limitation.
- "Connected" only means the settings were saved — not that they work. Inflowave can't verify SMTP credentials until it actually sends. After connecting, always click Send test: if it fails, the password is almost certainly your login password instead of an App Password (error 535).
Google Workspace gives you two completely different SMTP paths. Pick the wrong one and you will hit the 2,000/day cap when you thought you had 10,000.
Pick the path that matches your volume
User-level SMTP works for individual senders below 2,000 messages per day. SMTP Relay is for higher volume and for sending on behalf of multiple addresses in your domain. Most agencies and operators should use SMTP Relay.
The cap difference is published in Google's official Workspace sending limits documentation - it is not a soft limit you can negotiate. Hitting it returns 550 Daily user sending quota exceeded and the user's outbound is paused for 24 hours.
Option A - User-level SMTP (App Password)
Same flow as personal Gmail but on a Workspace domain. The 2FA prerequisite is mandatory and your Workspace admin must allow App Passwords org-wide.
- Sign in to
myaccount.google.comas the Workspace user. - Confirm 2-Step Verification is ON under Security.
- Visit
myaccount.google.com/apppasswords. - Name it "Inflowave", click Create.
- Copy the 16-digit passcode and paste into Inflowave with host
smtp.gmail.comport587.
If "App passwords" is hidden: Your Workspace admin disabled them. Two fixes - ask the admin to allow App Passwords org-wide (Admin console → Security → Authentication → 2-Step Verification → check "Allow users to turn on App Passwords"), or use the SMTP Relay path below instead.
Option B - SMTP Relay Service (10,000/user/day)
Only a Workspace super admin can configure this. Once configured, every user in the relay can authenticate via App Password OR (if you use a static egress IP) without any credentials.
- Sign in to
admin.google.comas a super admin. - Top-left menu → Apps → Google Workspace → Gmail → Routing.
- Scroll to SMTP relay service and click Configure.
- Name it (e.g. "Inflowave relay").
- Under Allowed senders, pick "Only registered Apps users in my domains" (strictest, recommended). If you need to send from external addresses, "Only addresses in my domains" works.
- Under Authentication, check Require SMTP Authentication if you will paste credentials in Inflowave. Check Only accept mail from the specified IP addresses if you have a static egress IP and want to skip credentials.
- Under Encryption, check Require TLS encryption.
- Click Save.
- Wait up to 24 hours for propagation (usually it is live in minutes).
Sub-host gotcha: If you accidentally type smtp.gmail.com instead of smtp-relay.gmail.com in Inflowave, the connection authenticates against the user-level path and silently caps at 2,000/day. Triple-check the host before saving.
Connect to Inflowave
- In Inflowave, open the client (account) you want to send for → Email tab → Add sending domain → Custom SMTP. This binds the mailbox to that one client. (Settings → Email works too, but set the Scope to the client — see the warning below.)
- Host:
smtp.gmail.com(Option A) orsmtp-relay.gmail.com(Option B). - Port:
587. - Username: Workspace email.
- Password: the 16-digit App Password.
- Click Save — this only stores the credentials, it does not verify them, so “Connected” means “saved”. Then click Send test on the domain card to actually confirm delivery.
Scope — keep it per-client. Connecting from Settings → Email defaults the Scope to “Agency default,” which makes this mailbox the From-address for your whole agency (every workspace/client without its own domain) — including transactional and system emails. To keep it to one client, set Scope to that client, or add it from the client’s own Email tab so it binds automatically.
An App Password belongs to ONE account
An App Password authenticates as the exact mailbox that generated it — not as your domain or your admin account. If you want Inflowave to send and receive as partnerships@yourdomain.com, generate the App Password while signed in as partnerships@ itself. An App Password made on the admin account authenticates as the admin, so it will only work for another address if that address is a verified “Send mail as” alias of the admin's mailbox. If the address is a pure alias (no separate login), connect with the underlying mailbox's username + that mailbox's App Password instead.
Receiving replies (two-way / IMAP)
The steps above only set up sending. For inbound mail (so replies and emails sent to this address show up in Inflowave), Inflowave polls the mailbox over IMAP, and two things must be true:
- Admin must enable IMAP org-wide. Admin console → Apps → Google Workspace → Gmail → End User Access → “POP and IMAP access” → check “Enable IMAP access for all users” for the org unit the mailbox is in, then Save (allow a few minutes to propagate). If IMAP is off, no App Password will let Inflowave read the inbox.
- The IMAP username must be the same mailbox as SMTP. Host
imap.gmail.com, port993, username = the full address you connected (e.g.partnerships@yourdomain.com— notsupport@or the admin), password = the same App Password.
A real user mailbox can be polled over IMAP. A Google Group cannot — groups have no mailbox to poll, so inbound to a group address won't appear this way; use a real user (or a send-as alias of one) instead.
Troubleshooting
App Password is wrong or revoked. Regenerate and paste again. If using SMTP Relay with IP whitelist, your egress IP is not on the allow-list.
The "From" address on your message is not a registered Workspace user. With Option B, the address must be in the domain you configured under "Only addresses in my domains".
You hit the cap (2,000 user-level or 10,000 relay). Wait 24 hours OR move to a dedicated sending provider for the affected user.
Google is rate-limiting per-second sends. Reduce concurrency in Inflowave or contact Workspace support to lift soft caps.
Official sending limits
- 2,000 messages per user per 24h via
smtp.gmail.com(user-level SMTP). - 10,000 messages per user per 24h via
smtp-relay.gmail.com(SMTP Relay). - 100 recipients per single SMTP transaction - exceeding this returns 5xx on the transaction.
- 4.6 million recipients per organization per 24h.
- 319,444 recipients per rolling 10-minute window across the org.
- The 24-hour rolling window resets at midnight Pacific time.
Official sources
- Google Workspace Knowledge - Route outgoing SMTP relay messages through Google
- Google Workspace Admin Help - SMTP relay service: Route outgoing non-Gmail messages
- Google Workspace Admin Help - Gmail sending limits in Google Workspace (the 2k/10k/4.6M numbers)
- Google Workspace Admin Help - Set up your device or app to send mail through Google Workspace
