On this page
Short answer
Download the Reply.io CSV from Outreach2day, add SMTP SSL and IMAP SSL columns set to on (ports 465 and 993 use SSL), and import it in Reply under Settings > Email Accounts > New email account > Import from CSV. Or add each mailbox with Other Provider. Set the daily limit to 25 and keep Reply's ramp-up on; warm-up keeps running in Outreach2day.
What you get
- A CSV in Reply.io's import format with the SMTP and IMAP settings of every mailbox you pick
- Warm-up keeps running in Outreach2day after the export, included in the price
- SPF, DKIM and DMARC already set on every domain
Export the CSV and import it into Reply.io
In Outreach2day
- Select mailboxes. Open Mailboxes and select the mailboxes to export, or export all of them
- Download the file. Click Export and pick Reply.io. The CSV downloads with one row per mailbox
In Reply.io
- Import the CSV. Settings > Email Accounts > New email account > Import from CSV, fill Reply's sample with the values and upload it (how.reply.io)
- Or add one mailbox. Settings > Email Accounts > New email account > Other Provider > Continue; enter email, sender name, SMTP and IMAP host and port and the password, then Test until both dots are green (how.reply.io)
- Check the mailboxes. A red dot next to an account means a problem; hover over it for Reply's hint (how.reply.io)
Fields in the Reply.io CSV
The file from the Reply.io export has these columns:
| Column | Value |
|---|---|
Email | The mailbox address |
Daily Limit | 50 |
Sender Name | Sender first and last name |
SMTP Host | outreachmailstream.com |
SMTP Port | 465 |
SMTP Password | The mailbox password |
IMAP Host | outreachmailstream.com |
IMAP Port | 993 |
IMAP Password | The mailbox password |
- The columns follow Reply's sample file, in its order; Reply uses the email address as the username
- Reply's sample also has SMTP SSL and IMAP SSL. Our file leaves them out: add both and set SSL on, in the form Reply's sample shows, because both ports use SSL
- Daily Limit is 50 in the file; set 25 for Outreach2day mailboxes
Connection settings
To add a single mailbox by hand, or to check what Reply.io saved, use these settings:
| Field | Value |
|---|---|
| SMTP host | outreachmailstream.com |
| SMTP port | 465 (SSL/TLS) |
| IMAP host | outreachmailstream.com |
| IMAP port | 993 (SSL/TLS) |
| Username (SMTP and IMAP) | The full email address |
| Password (SMTP and IMAP) | The mailbox password from the export (the same for SMTP and IMAP) |
Sending settings per mailbox
- Mailboxes can send cold email 14 days after warm-up starts; warm-up keeps running after that
- Up to 25 cold emails per mailbox a day, warm-up not counted
- Start low on day 14 (for example 5 a day) and reach 25 around day 21
- To send more, add mailboxes and domains; keep the per-mailbox number at 25
Where to set it in Reply.io:
- Daily Limit per mailbox: Settings > Email Accounts > the mailbox > Safety settings (set 25). Reply's ceiling is 400 a day on paid plans (how.reply.io)
- Delay between emails: Reply's default is a random 5 to 7.5 minutes (how.reply.io)
- Ramp-up (Safety settings) is on by default for new accounts: it starts at 10 a day and adds 3 a sending day (how.reply.io)
Why 25: how many cold emails one mailbox should send a day. The day-by-day ramp: email warm-up schedule.
Warm-up
Warm-up for Outreach2day mailboxes runs in Outreach2day and is included in the price. It keeps running after you export the mailboxes, whichever tool sends from them, so the other tool's warm-up is optional.
- Reply's warm-up runs in MailToaster, one warm-up seat per mailbox on paid plans; the Import to MailToaster checkbox appears when you add an account (how.reply.io)
Keep warm-up on while the mailbox sends: should I keep warm-up running while sending.
DNS and tracking domain
- SPF, DKIM and DMARC for every Outreach2day domain are set and checked automatically; you add nothing for sending
- A custom tracking domain is a CNAME on a subdomain of your sending domain. For a domain whose DNS Outreach2day hosts, add it in the app: Domains, open the domain, Manage DNS records, Add record (type CNAME). For a domain whose DNS stays at your registrar, add it there
- A tracking domain matters only with open or click tracking on. In the first cold email, leave out the tracking pixel and links and measure replies (see the answer on open tracking below)
- Reply's custom tracking needs one CNAME and one TXT record per link type (opens, clicks, opt-out), for example opens.yourdomain.com; the record values are shown in Reply when you set it up (how.reply.io)
More on tracking: do open tracking and links hurt cold email deliverability.
Troubleshooting
| Error or symptom | Fix |
|---|---|
| Red dot next to the account | Hover for Reply's hint. Accounts added by hand have no Reconnect button: remove and add them again (how.reply.io) |
| Generic domains such as gmail.com rejected | Outreach2day mailboxes are on your business domains, so this doesn't apply to them (how.reply.io) |
| No free warm-up seats | Only if you warm up in MailToaster; Outreach2day warm-up needs no seat (how.reply.io) |
| Authentication failed / invalid credentials | Use the full email address as the username and the password from a fresh export. A disabled mailbox is exported with an empty password, so it can't connect |
| Connection timed out or SSL/TLS handshake error | Use SMTP port 465 with SSL/TLS and IMAP port 993 with SSL/TLS, both on outreachmailstream.com. Check that the tool did not switch the security setting to STARTTLS or none |
| Mailbox connects but can't send yet | Check the mailbox in Outreach2day: new mailboxes are being set up for up to 24 hours, and cold email starts 14 days after warm-up starts |
| Mailbox disconnected after it worked | Reconnect it in the tool with the same settings. With a one-click connection (Instantly, Smartlead) and auto-reconnect on, Outreach2day reconnects it for you |
If bounces climb after the mailboxes connect, look at the list: why a cold email bounce rate gets too high.
FAQ
How many mailboxes can I add to Reply.io?
Reply's specification lists 2 included accounts on the trial, 5 (monthly) or 10 (annual) on Multichannel and unlimited on Agency, with extra mailboxes at $29 a month. Check your plan before a large import.
Can Reply.io add mailboxes through its API?
Yes. Reply's API has an endpoint to connect a custom SMTP or IMAP mailbox (POST /v3/email-accounts). Outreach2day has no one-click export to Reply; use the CSV or the API with the settings on this page.
Do I need MailToaster for Outreach2day mailboxes?
No. Warm-up for Outreach2day mailboxes runs in Outreach2day and keeps running after you add them to Reply.
Sources
Reply.io documentation, read on 2026-10-09. Menus and field names change; if a step differs, Reply.io's own page is the reference.
- Reply.io: Email accounts specification: how.reply.io/specifications/email-accounts
- Reply.io: Connect a mailbox: how.reply.io/how-to/connect-a-mailbox
- Reply.io: Configure sending limits: how.reply.io/how-to/configure-sending-limits
- Reply.io: Warm up new mailboxes: how.reply.io/workflows/warm-up-new-mailboxes
- Reply.io: Deliverability: how.reply.io/capabilities/deliverability
- Reply.io API: Create an email account: docs.reply.io/api-reference/email-accounts/create-an-email-account
