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Questions most frequently asked:

How to Change the Default Language of an Automatic Link?

When Mailpro automatically inserts a link in your email — the unsubscribe link, the “view in browser” link, the “forward...

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How to Manage Unsubscribe Link for SMTP Messages?

Even when you send through SMTP from your CRM or your own application, every commercial message in 2026 must include...

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How Are Statistics Collected from an SMTP Sending?

An SMTP send is fast and silent: your application hands the message off, the relay delivers it, and unless something...

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Where Do I Find the SMTP Authentication Credentials in Mailpro?

To send messages through Mailpro’s SMTP relay you need four pieces of information: server host, port, username and password. They...

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What Type of SMTP Server to Choose?

Choosing the right SMTP server is one of the most consequential technical decisions for any business that sends email at...

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What Is the Maximum Weight of a Message Sent Through SMTP?

Mailpro’s SMTP relay accepts messages up to 20 MB total, including the email body, headers and all attachments after Base64 encoding...

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What’s the difference between SMTP and API?

Both SMTP and a transactional Email API send messages from your application to your customers, but they take different paths...

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What Is an SMTP Server? How SMTP Relay Works and Why You Need It

An SMTP server (Simple Mail Transfer Protocol) is the dedicated server that handles outgoing email. When your application, CRM or...

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Why Does My Email Look Strange on Outlook?

Outlook is the email client most likely to make your beautiful campaign look broken — clipped images, lost background colors,...

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What Is IP Reputation and Why Does It Matter?

IP reputation is the trust score that mailbox providers (Gmail, Yahoo, Outlook, Apple Mail) assign to the IP address that...

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File Sizes and Extensions Supported by Mailpro Builder

The Mailpro Builder accepts a wide range of file types for images, attachments and downloadable resources. Each type has a...

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MSISDN: Definition and Format (CC+NDC+SN)

MSISDN stands for Mobile Station International Subscriber Directory Number. It is the worldwide format your SMS gateway uses to identify...

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How to Schedule an SMS Campaign with Mailpro

Scheduling an SMS campaign in Mailpro lets you prepare the message in advance and have it delivered at the exact...

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How to Import Your SMS Phone List

Before launching your first SMS campaign in Mailpro, you need to import your phone list correctly. Follow these steps to...

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How to Send an Email as SMS with Mailpro: Gateway Guide

Mailpro’s Email-to-SMS gateway lets you trigger an SMS just by sending an email. The gateway converts the email into a...

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How to Personalize Your SMS With Mailpro

Personalized SMS messages outperform generic ones by 2–4× on click and reply rates. Mailpro’s SMS platform supports merge tags so...

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Country Phone Codes List for SMS Marketing

To send an SMS through Mailpro, every mobile number in your contact list must be in international (E.164) format: a...

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How to Use Mailpro’s Double Opt-In Functionality

Activating Mailpro’s double opt-in feature is the safest way to grow a clean, GDPR-compliant subscriber list. This guide walks you...

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What Is a Double Opt-in Subscription?

Double opt-in is the subscription process where a new subscriber must confirm their email address by clicking a link in...

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How to Configure DMARC With Mailpro: 5-Step Safe Rollout

Setting up a DMARC record with Mailpro is the third pillar of email authentication, after SPF and DKIM. Done right,...

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