How to Configure PlusVibe Delivery Settings for ColdSend Inboxes

ColdSend inboxes are powered by Azure Communication Services (ACS), which enforces a hard limit of 100 emails per hour per domain. This limit is shared across every platform sending from that domain — including ColdSend itself.

If you exceed this limit, emails are hard rejected (not queued). This guide shows you exactly what values to set in PlusVibe's delivery settings to stay within the quota.

Prerequisite: This guide assumes you've already connected your ColdSend inboxes in PlusVibe. If you haven't, follow this guide first: How to Export Inboxes from ColdSend and Connect Them in PlusVibe

Understand the Domain Quota

Before setting your delivery values, you need to understand three things:

1. The limit is per domain, not per inbox. Whether you have 1 inbox or 100 on the same domain, the combined sending across all of them cannot exceed 100 emails per hour.
2. The limit is shared across platforms. If ColdSend is also sending emails (campaigns, warmup) on the same domain, those emails count toward the same 100/hour pool.
3. Exceeding the limit causes hard rejections. Emails that go over the quota are not queued or retried — they simply fail.

How to Access Delivery Settings in PlusVibe

Unlike some platforms that configure limits per campaign, PlusVibe applies delivery settings at the email account level — meaning the limits apply across all campaigns using that inbox.

To configure delivery settings for your ColdSend inboxes:

1. Go to Email Accounts & Warm-up.
2. Use the search bar to find your domain.
3. Click the select all checkbox to select all inboxes for that domain.
4. Click the Bulk Actions dropdown and select Edit Settings.

PlusVibe Bulk Edit Settings

1. In the panel that opens, locate the Delivery Settings section.
2. You'll see two fields:
   • Daily Campaign Email Limit — maximum emails per inbox per day
   • Minimum Interval In Minutes — minimum time between consecutive emails from the same inbox

PlusVibe Delivery Settings

Which Case Applies to You?

Choose the case that matches your setup:

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Case A: PlusVibe Only

Use this case when your ColdSend inboxes are connected in PlusVibe but you are not actively sending campaigns or running warmup from ColdSend on the same domain.

Your full domain quota of 100 emails/hour is available for PlusVibe.

The Formula

Minimum Interval (minutes) = (Number of active inboxes × 60) ÷ 100   ← round UP
Daily Campaign Email Limit = (100 ÷ Number of active inboxes) × Sending hours

Quick Reference Table

How to Apply

1. Count how many inboxes from the same domain are active in PlusVibe.
2. Find the matching row in the table above.
3. Follow the steps in How to Access Delivery Settings above.
4. Set:
   • Daily Campaign Email Limit — use the value from the table (adjust for your sending hours)
   • Minimum Interval In Minutes — use the value from the table
5. Save the settings.
6. If your inbox count falls between two rows, use the higher interval (more conservative).

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Case B: ColdSend + PlusVibe

Use this case when you're actively running campaigns or warmup in ColdSend and sending from PlusVibe on the same domain.

Your domain quota of 100 emails/hour must be split between ColdSend and PlusVibe.

Step 1: Estimate ColdSend's Hourly Usage

Check how many emails per hour ColdSend is sending on the domain. This includes:

• Active campaigns — check your campaign's sending rate in ColdSend
• Warmup emails — each inbox in warmup sends a small number of emails per hour

Tip: A rough estimate is fine. If you have 20 inboxes in warmup with a warmup limit of 2/day each, that's roughly 40 emails spread across the day — about 2–3 per hour. Active campaigns are easier to estimate from the daily limit divided by sending hours.

Let's call this number S (ColdSend emails per hour).

Step 2: Calculate Your Remaining Budget

Remaining budget (R) = 100 − S

Example: If ColdSend is sending ~20 emails/hour, your remaining budget for PlusVibe is 80 emails/hour.

Step 3: Apply the Formula

Minimum Interval (minutes) = (Number of active inboxes × 60) ÷ R   ← round UP
Daily Campaign Email Limit = (R ÷ Number of active inboxes) × Sending hours

Quick Reference Tables

If ColdSend uses ~20 emails/hour (R = 80):

If ColdSend uses ~40 emails/hour (R = 60):

If ColdSend uses ~60 emails/hour (R = 40):

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General Formula (Custom Values)

If your setup doesn't match the tables above, use this formula directly:

Inputs:

• N = number of inboxes from the domain active in PlusVibe
• S = emails per hour ColdSend is sending on the same domain (0 if not using ColdSend)
• R = 100 − S (remaining hourly budget for PlusVibe)
• H = number of hours per day your campaigns will be active

Outputs:

• Minimum Interval In Minutes = (N × 60) ÷ R ← round UP
• Daily Campaign Email Limit = (R ÷ N) × H ← round DOWN

Important: Always round the interval up and the daily limit down to stay safely under the quota.

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Campaign Email Ramp-Up

PlusVibe includes a Campaign Email Ramp-Up toggle in the same Delivery Settings panel. When enabled, PlusVibe gradually increases your daily sending volume over time until it reaches your configured Daily Campaign Email Limit.

When to use it:

• New inboxes that haven't been warmed up yet
• Domains with no prior sending history
• High-risk lead segments where you want to start conservatively

Important: Ramp-up does not override the domain quota. It only controls how quickly PlusVibe approaches the limit you've set. The domain-level 100/hour hard limit still applies regardless of ramp-up settings.

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Common Mistakes to Avoid

Setting the Same Interval Without Counting Inboxes

The most common mistake is setting a 5-minute interval on every inbox, assuming each has its own limit. With 100 inboxes on a domain, a 5-minute interval would attempt ~1,200 emails per hour — far above the 100/hour limit.

Forgetting ColdSend's Own Sending

If ColdSend is actively sending campaigns or warmup on the same domain, those emails count. Ignoring this will cause rejections even if your PlusVibe settings look correct on their own.

Not Realizing Settings Are Per Account, Not Per Campaign

PlusVibe's delivery settings apply to the email account, not to individual campaigns. If you run two campaigns using the same inbox, both draw from the same daily limit and interval. Make sure the combined volume across all campaigns stays within your calculated values.

Not Adjusting When Adding More Inboxes

If you add more inboxes to PlusVibe later, you must increase the interval and decrease the daily limit accordingly. The quota doesn't grow with more inboxes — it's fixed per domain.

Ignoring Warmup Volume

If PlusVibe's warmup is enabled on the same inboxes, warmup emails count toward the domain quota. Factor warmup volume into your calculations, especially for new inboxes with aggressive warmup settings.

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Troubleshooting

Emails Are Being Hard Rejected

• Verify your interval and daily limit match the formulas above
• Check if ColdSend is sending more than you estimated — look at your ColdSend campaign stats for the domain
• Count the actual number of active inboxes on the domain in PlusVibe (some may have been added without your noticing)

Sending Feels Too Slow

This is expected with a shared domain quota. To increase throughput:

• Use more domains — spread your inboxes across multiple sending domains, each with its own 100/hour quota
• Reduce ColdSend's usage — pause warmup or lower campaign volume in ColdSend to free up budget for PlusVibe
• Run fewer inboxes at a time — use a subset of your inboxes in PlusVibe and rotate them

Some Inboxes Send Fine but Others Don't

• Check if all inboxes are on the same domain — if some are on different domains, they have separate quotas
• Verify no inbox has been disconnected or has invalid credentials in PlusVibe
• Ensure you applied the bulk edit settings to all inboxes on the domain, not just a subset

Still Need Help?

Contact ColdSend support at support@coldsend.pro or join our Discord server — we're happy to help you troubleshoot your setup.

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FAQs

What happens if I set the interval too low?
Your domain will exceed the 100 emails/hour limit and ACS will hard reject the excess emails. These emails are not retried — they're lost. Always err on the side of a higher interval.

Can I use all 100 inboxes from my domain in PlusVibe?
Yes, but each inbox will only send about 1 email per hour (or less if ColdSend is also sending). This works for large lead lists where you don't need high throughput per inbox.

Does warmup in PlusVibe count toward the domain limit?
Yes. Any email sent through the inbox — whether it's a campaign email, a warmup email, or a follow-up — counts toward the 100/hour domain quota. If PlusVibe's warmup is running alongside campaigns, factor that into your calculations.

How do I know how many emails ColdSend is sending per hour?
Check your ColdSend campaign settings for the daily limit and sending window. Divide the daily limit by the number of sending hours to get the hourly rate. Add any warmup volume on top.

Can I run campaigns on ColdSend and PlusVibe at the same time?
Yes, as long as the combined hourly volume across both platforms stays under 100 emails per domain. Use Case B above to calculate the correct split.

What if I have inboxes on multiple domains?
Each domain has its own independent 100/hour quota. Apply the formula separately for each domain. When using bulk edit, make sure you've filtered to only one domain at a time.

Do the delivery settings apply per campaign or per inbox?
Per inbox. The Daily Campaign Email Limit and Minimum Interval apply to the email account itself, across all campaigns that use it. This is different from platforms like Instantly where limits are set per campaign.