Twilio error 30020 means a carrier is throttling or outright rejecting your messages because you are sending to their subscribers faster than their network accepts traffic from your sending number or campaign. This is distinct from Twilio's own account-level queue limit (error 30001): 30020 is a rejection that happens after Twilio has accepted your message and forwarded it to the carrier. Fixing 30020 requires matching your throughput to the carrier-specific rate limits for your number type and registration tier.
What Causes This Error
The most common cause for long code senders is exceeding the 1 message per second per number rate that US carriers enforce for newly registered or low-tier 10DLC long codes. Registered 10DLC campaigns with approved throughput levels of 15 MPS can still hit 30020 if you send at maximum throughput to a single carrier's subscriber base without distributing sends across your number pool. Short code senders can also hit 30020 when sending blast campaigns above the carrier-approved TPS rate for their specific short code, which is set during the short code provisioning process. International high-volume campaigns to carriers in markets with strict anti-spam infrastructure, such as Germany, France, and Japan, frequently generate 30020 because those carriers apply lower per-sender thresholds than US carriers.
How to Fix It Step by Step
Identify which carrier is returning the 30020 errors by examining the carrier field in your StatusCallback payloads or by using the Twilio Lookup API on the destination numbers. Reduce your send rate to that carrier's subscriber numbers immediately: for US long codes, cap at 1 message per second per number; for A2P 10DLC campaigns, check your approved throughput in the Console under Messaging, then Senders, then your campaign registration. If you need higher throughput than your current registration allows, navigate to the TCR portal linked from your Twilio Console campaign page and request a throughput upgrade by providing supporting evidence of your opt-in volume and send frequency. For immediate relief on a bulk campaign already in progress, pause the send job, wait 5 minutes for the carrier rate limiter to reset, then resume at a lower TPS by adding an inter-message delay in your queue processor.
How to Prevent It from Recurring
Calculate your required messages-per-second rate before every bulk campaign by dividing total message volume by your acceptable send window in seconds, then verify this rate is within your registered 10DLC campaign's approved throughput shown in the Console. Use a Twilio Messaging Service rather than a single number for campaigns that need throughput above 1 MPS, as Messaging Services with a pool of 10DLC numbers distribute sends across multiple originating numbers and multiply your effective throughput by the pool size. Implement adaptive rate limiting in your queue processor: read the StatusCallback error codes in real time and automatically reduce throughput when the 30020 rate exceeds 1 percent of sends in a rolling 60-second window. For international campaigns, pre-validate carrier throughput limits by country by consulting Twilio's international messaging documentation and setting country-specific TPS caps in your campaign scheduler.
When to Call a Specialist
If you have correctly registered your 10DLC campaign and set throughput rates within the approved limits but are still seeing 30020 errors, the campaign approval may have an error in the throughput field that requires Twilio support to correct in the backend registration. A specialist is essential if you are running a high-volume SMS operation exceeding 10,000 messages per day, where throughput planning, number pool sizing, and campaign registration all need to be optimized together to avoid rate limit collisions. You should also escalate if 30020 errors appear on a short code program, as short code rate limits are set contractually at provisioning and changes require a formal amendment to your short code agreement. Unresolved rate limiting on a live broadcast campaign causes message loss that cannot be recovered after the send window closes.
Conclusion
Error 30020 is a throughput mismatch between your send rate and the carrier's acceptance rate, and the fix is always to align your rate to the registered and approved limit. If this error is blocking your production system, contact our team and we will diagnose and fix it within the hour.
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