Take control of your communication deliverability by learning how to reduce email bounces and follow SMS content regulations to ensure your messages reach your clients.
As your contact list grows, you might see some emails bounce due to typos, inactive addresses, inbox bots, or strict mail servers. A few bounces are normal but too many can hurt your sender reputation or get your tools flagged.
By following specific guidelines, you can reduce bounces and keep your emails landing in the right inboxes.
What is an email bounce?
An email bounce happens when a marketing or promotional email cannot be delivered to the recipient’s inbox. It is like the message tried to reach someone but got sent back instead. Emails can bounce for many reasons, and too many bounces can hurt your sender reputation. If email servers see a high bounce rate, they may start blocking your messages altogether.
Two types of email bounces
There are two kinds of email bounces to know about: soft bounces and hard bounces.
Soft Bounce
A soft bounce means the email address is valid but the message could not be delivered. This usually occurs for temporary reasons like a full inbox, a server issue, or a message that is too long.
Hard Bounce
A hard bounce happens when an email cannot be delivered because the address is invalid or does not exist. Since this is a permanent issue, you must remove that address from your list.
What causes emails to bounce?
The email does not exist
If a bounce is marked as "non-existent email address," it could mean there is a typo in the address or the person may no longer be with the organization.
The email is suspended
The email address may be suspended not just for bouncing your emails, but also for bouncing emails from other senders.
The email is blocked
If email addresses are in the "Blocked" category, it means the receiving server has blocked your email. This is common with organizations like government offices or schools, where email servers tend to be more strict about what they accept.
The email could not be delivered
If bounced emails fall under the "Undeliverable" category, it usually means the recipient's email server is temporarily down, too busy, or could not be found.
The mailbox is full
If your contact’s inbox is full, your emails will bounce back until there is space for them. This could also mean they no longer use that email address. Some email providers, such as Outlook, have storage limits on their basic plans as low as 15GB. This can cause an inbox to fill up faster than expected.
The recipient has an auto-reply set up
If someone has an auto-reply set up, like when they are on vacation, your emails may bounce. However, unlike other bounce types, this means your email reached their inbox successfully. They just cannot access it at the moment.
How to reduce your email bounce rate
Bounces can hurt your email list growth by affecting your deliverability and the overall success of your campaigns. Keep a close eye on bounce rates and address any issues quickly.
Remove an email address from your list
If an email is a hard bounce, remove that address from your list right away. The best way to remove these addresses from your email list is to unsubscribe them.
Recommended tools for email validation
Manually checking every email on your client list can be time-consuming, but you do not have to do it alone. There are reliable tools that can quickly validate your email addresses, helping ensure your messages reach real, active inboxes.
Here are a few websites we recommend exploring:
- Mailbox Layer: This email validation tool lets you check a few email addresses for free. If you need to verify larger lists, they also offer subscription plans with more features.
- NeverBounce: Like Mailboxlayer, NeverBounce helps clean up your contact list by verifying email addresses and removing invalid ones.
SMS Content Restrictions
SMS is a highly regulated communication channel with strict rules and carrier requirements. Prohibited content will be automatically blocked by carriers. Age-restricted content may require extra steps like age verification. If your business plans to send restricted content, SMS may not be the most suitable option for customer communication.
Prohibited SMS Content
The following message categories are prohibited for SMS and MMS:
- High-risk financial services
- Third-party lead generation
- Debt collection and forgiveness
- "Get rich quick" schemes or multi-level marketing
- Illegal substances
- Gambling
- Sex, hate, alcohol, firearms, and tobacco (SHAFT)
What is SHAFT?
SHAFT is an acronym designed to help you remember the types of content that are either prohibited or have specific rules.
- S: Sexually inappropriate content
- H: Hate speech or profanity
- A: Alcohol
- F: Firearms, depictions, or endorsements of violence
- T: Tobacco (including vaping) or endorsement of illegal or illicit drugs, including marijuana and cannabis
Prohibited Category Details
High-risk financial services
This includes payday loans, short term high-interest loans, third-party auto or mortgage loans, student loans, and cryptocurrency. "Third-party" refers to anyone who is not the lender or the company managing the loan. SMS messages that offer financial investment advice, tips, or details about loans and refinancing are not allowed. Carriers also block messages that include links to donation sites.
Third-party lead generation services
The buying, selling, or sharing of consumer information is strictly prohibited. Only the business that obtained consent sends SMS messages. "Cold" outreach to potential customers who have had no previous contact with the company is strictly prohibited.
Debt collection or forgiveness
Nearly all debt consolidation and forgiveness services are prohibited for SMS and MMS. For debt collection, the business owed the debt can send payment reminders and personalized messages. However, a third party cannot attempt debt collection through SMS or MMS.
"Get rich quick" schemes or Multi-level marketing
Work-from-home programs, risk investment opportunities, and pyramid schemes are not allowed. Multi-level marketing (MLM) products associated with unsolicited commercial messages (spam) are prohibited.
Illegal substances
Cannabis is federally illegal in the United States, so cannabis businesses cannot use SMS/MMS messaging in the US, regardless of the content. While CBD is federally legal, it is not legal in all US states and US carriers do not permit messaging related to CBD. Additionally, offers for drugs that cannot be sold over-the-counter in the US or Canada are prohibited.
Gambling, Alcohol, Firearms, and Tobacco
Gambling traffic, Alcohol, Firearms, and Tobacco traffic are prohibited on Toll-Free numbers. These are allowed on Short Codes or Long Codes if you follow proper age-gating procedures. Vaping-related traffic is never allowed.
Frequently Asked Questions
Q: What is the bounce rate limit on the platform and what happens if I exceed it?
The platform allows a bounce rate of up to 3%. To follow anti-spam rules, if your campaigns hit this limit three times, the platform permanently blocks your account from sending promotional messages.
Q: Can I send SMS messages about CBD products if they are legal in my state?
No, US carriers do not permit messaging related to CBD because it is not legal in all US states. Additionally, cannabis businesses cannot use SMS/MMS messaging in the US because it remains federally illegal.
Q: What should I do if an email address results in a hard bounce?
You should remove that address from your list immediately by unsubscribing them. This helps protect your sender reputation and prevents your account from being flagged by email servers.
Q: How often should I clean my contact list to maintain a low bounce rate?
It is a best practice to review your contact list every few months or before launching a major marketing campaign. Regular maintenance ensures you are not sending messages to inactive or invalid addresses.
Q: Does the platform automatically retry sending emails after a soft bounce?
Yes, the platform will typically attempt to redeliver emails that result in a soft bounce. However, if the issue persists over multiple attempts, it may eventually be categorized as a failure to protect your deliverability.
Q: Why was my SMS message blocked even though it did not contain prohibited content?
Carriers use automated filters to detect spam. If your message contains shortened URLs from public link shorteners, excessive capitalization, or looks like a generic broadcast without personalization, it might be flagged and blocked by the carrier.
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