The 5 Biggest Mistakes for A2P Messaging

Business messaging is one of the most powerful ways to communicate with customers ⚡️, but it’s also one of the easiest to get wrong 🛑. Between carrier rules, throughput limits, compliance requirements, and message strategy, companies often make avoidable mistakes that cost them deliverability, engagement, and revenue 📉

Today we’re exploring the five biggest mistakes businesses make with SMS, and how you 🫵 can avoid them to ensure your messaging is compliant, effective, and scalable 📈

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🚦 1. Not Understanding Throughput Limits

Throughput is the number of messages you can send within a defined time window. Carriers enforce these limits differently, and misunderstanding them can tank your deliverability.

📱 T-Mobile: Daily Limits

T-Mobile uses daily caps at the brand (EIN) level, starting at 2,000 messages/day. With higher trust scores, brands can scale up to 200,000/day.

Your trust score is determined largely by:

• Age of the business

• Number of employees

Higher scores = higher throughput.

⏱️ AT&T: Per-Minute Limits

AT&T measures throughput per-minute at the campaign level, not the brand level.

Starting throughput:

• 240 SMS/minute

• 120 MMS/minute

With standard vetting, this increases to:

• 4,500 SMS/minute

• 2,400 MMS/minute

🧠 Key Distinction

• T-Mobile → Brand level, daily

• AT&T → Campaign level, per minute

This affects how you structure your campaigns and scale your traffic.

💬 2. Sending Messages That Don’t Garner a Response

The biggest messaging mistake? Sending texts that don’t spark engagement.

A message like:

“Hey, I have a great deal for you.”

…does nothing to provide value. It looks spammy, vague, and untrustworthy.

✍️ Instead, craft messages that:

• Communicate clear value

• Are concise but informative

• Include a call to action

• Set expectations for the next step

Example of a response-driven message:

“Hi Sarah! We’re offering a complimentary tune-up this week. I have openings at 3 PM or 5 PM tomorrow — which works better for you?”

👀 Why it matters

SMS has a 98% open rate, but people skim. Your message must immediately deliver value or prompt action.

🔁 3. Sending Reactivation Messages All at Once

Reactivation campaigns target your past customers, old leads, or referral prospects. But sending these messages in one large blast is a major red flag for carriers.

❌ Why This Causes Problems

Past customers often:

• No longer need your service

• Changed circumstances (e.g., EV = no more oil changes)

• Aren’t expecting outreach

This leads to high opt-out rates.

If your normal opt-out rate is 0–1%, but your reactivation blast spikes to 10%, carriers may:

• 🚫 Flag your number
• 🚫 Block or restrict your traffic
• 🚫 Lower your trust score

✅ The Fix: Drip Your Reactivations

Blend old contacts into your daily traffic:

• Send 10–20 per day

• Distribute across multiple days/weeks

• Keep opt-out patterns consistent

This protects your deliverability and carrier reputation.

🔌 4. Using the Wrong Messaging Channel

Choosing the wrong channel is one of the most common — and costly — mistakes.

📍 Use 10DLC When:

• You operate locally or regionally

• You want high response rates

• You rely on two-way conversational messaging

People recognize local numbers and trust them more 💡

📞 Use Toll-Free When:

• You’re a national brand with a central presence

• You don’t rely heavily on conversational SMS

• You want a consistent nationwide identity

Toll-free is great for large brands like Google or Apple communicating at scale 💡

🧨 What NOT to do

Don’t send conversational messaging through:

• Short codes

• Toll-free numbers (if responses matter)

Most consumers don’t even realize they can reply to those channels.

📊 5. Choosing the Wrong Campaign Type

Businesses often misunderstand when to use standard vs. low-volume campaigns, and which sub-use cases to include.

🌐 Standard Campaigns

Best for businesses sending 4,000–6,000+ messages/day.

Why?

• You’ll inevitably exceed low-volume limits

• Conversations bleed into the next day

• Scaling requires higher throughput

💡 Low-Volume Campaigns

Ideal for companies sending 1,000–3,000 messages/day.
Bonus: saves you $8.50/month 💰

🏷️ Recommended Sub-Use Cases

Always include:

• 📣 Marketing

• 🛠️ Customer Support

• 🔔 Account Notifications

These three cover 99% of business messaging needs.

🔐 What About 2FA?

You can include it in the same campaign, but best practice:
👉 Use a separate dedicated 2FA campaign for higher throughput and safer deliverability.

🏁 Final Thoughts

These are the five most common mistakes companies make when entering the messaging ecosystem — and avoiding them can dramatically improve your deliverability, engagement, and customer experience.

At Signal House, we help businesses send high-quality, fully compliant SMS and MMS traffic from their own software and workflows. If you need help building or optimizing your messaging infrastructure, we’re here for you 💜