Carrier blockage may occur anytime for various reasons carriers do not disclose. When it occurs, carriers block specific SMSes, causing them not to be delivered to your leads.

Note: Carriers do not block your account or the number/s used for a campaign. The blockage influence only SMS sent, thus, you do not need to delete your approved numbers.

There are some general recommendations that should help avoid high blockage and keep the block rate at its minimum:

1. Keep no more than ONE approved number per the area code you market to. This usually produces better deliverability and a lower block rate than if you used more than one number with the same area code.

2. Do not change your approved numbers often. The numbers you purchased and got approved with carriers are linked to your registration, so it’s recommended to stick to them. Using the same numbers for a long time helps build your trust score with carriers and improve deliverability.

3. Ensure the campaigns you send align with the campaign description provided when registering your brand with A2P 10DLC.

4. Use varying message templates. Keep your message templates clear and informative to avoid flagging them as spam. Also, it’s recommended to introduce yourself (with your own or company name) in your templates.

If some messages have been blocked, you can export the carrier-blocked numbers from the campaign screen and then create a new campaign to try sending a message to those contacts again. Check out this support article for step-by-step instructions.