Outbound reachability issues can occur for many reasons, including carrier restrictions, regional dialing rules, regulatory limitations, or account configuration. This guide brings together several country specific issues into one resource to help you understand why a call may fail and what you can do to resolve it.
How to use this guide
This article is organized into the following sections:
- Country specific reachability issues
- General outbound calling restrictions
- Troubleshooting unreachable or forbidden numbers
- When and how to contact Support
Each section includes symptoms, causes, and the steps you can take to resolve the issue.
Important: Many limitations described in this article are due to regulatory or carrier rules that Aircall cannot override. In these cases, switching number types or requesting assistance from Support is required.
1. Country specific reachability issues
Thailand: cannot make outbound calls from Thai numbers (+66)
Symptoms
Outbound calls from your Thai number (+66) fail.
Cause
Some partner carriers that provide Thai numbers support inbound calls and messages only, meaning outbound calling is not available on those numbers.
Solution
Aircall partners with multiple carriers, including one that supports outbound local and international calls in E164 format, supports DTMF, and does not allow outbound toll free calling.
If you want your Thai number moved to an outbound capable carrier or want to request a new Thai number on this carrier, please contact Aircall Support.
Tip: Include your Thai number and example failed call attempts to speed up processing.
Spain: outbound calls fail from numbers starting with +34 902
Symptoms
Calls do not connect when dialing from a Spanish national number beginning with +34 902.
Cause
Spanish 902 numbers are restricted to inbound calling only by carriers and regulators. They cannot be used for outbound calls.
Solution
If you need to make outbound calls from Spain, use another type of Spanish number. Aircall offers +34 518 national format numbers and a range of local geographic numbers.
Note: The restriction applies only to 902 numbers. All other Spanish number types provided by Aircall support outbound calling.
Argentina: international calls to mobile numbers do not connect
Symptoms
Calls to Argentinian mobiles fail when dialing from non Argentinian numbers. Returning missed calls to Argentinian mobiles fails.
Cause
Argentina requires a specific formatting rule for international calls to mobile numbers:
Add 9 after +54, and remove the 15 prefix if present.
Inbound calls from Argentinian mobiles appear without the required 9, so directly returning the call will fail unless the number is corrected.
Solution
Format the number correctly before dialing:
- For (11) 1234-5678, dial +54 9 1112345678
- For (11) 15 8765-4321, dial +54 9 1187654321
Important: Always ensure the number includes the 9 and excludes the 15 before calling any Argentinian mobile. Saved contacts must be updated as well.
Australia: number invalid when calling government departments and public sector agencies
Symptoms
Calls to Australian agencies such as the Passport Office, ATO, Medicare, banks, or healthcare institutions may fail with the message:
“The number is invalid or the number is blocked.”
Cause
A partner carrier may temporarily restrict some calls to prevent fraud. Their verification model may occasionally flag legitimate calls as suspicious.
Solution
Contact Aircall Support including:
- The affected 1300 / 131 / 132 number
- Call samples or call UUIDs.
Note: Once the number is whitelisted, calling and recording will work normally.
Australia: outbound calls fail from 13, 1300, 1800, or 1900 numbers
Symptoms
Outbound calls fail when using numbers beginning with 13, 1300, 1800, or 1900.
Cause
These number types are designed for inbound calls only. Outbound calling is not permitted under Australian carrier and regulatory rules. For more information, please see our article Australian Toll-Free and Special Numbers Restrictions.
Solution
If you need to place outbound calls from Australia, use an Australian geographic number instead. These can be purchased in the Aircall Dashboard or requested to Aircall Support.
Tip: If you regularly call customers in Australia, consider switching your main outbound caller ID to a geographic number for more consistent deliverability.
2. General outbound calling restrictions
Number is blocked when calling overseas
Symptoms
International calls or calls to special or high cost destinations fail, and you receive the message: “This number is blocked.” Local numbers can be called by the same Aircall phone number
Cause
You may be trying to reach a destination not included in your Aircall plan or a number type that Aircall blocks by default for safety reasons.
Solution
Contact your Account Manager or Aircall Support to request activation of the required calling feature.
If you are on a trial account, review Trial Account Limitations and Call Pricing.
Important: Aircall will not automatically enable access to high risk or high cost destinations. Feature activation is required to avoid unexpected charges.
3. Troubleshooting unreachable or forbidden numbers
Symptoms
A specific number will not connect, calls end immediately without ringing, no trace appears in your dashboard, or you hear: “This number is forbidden.”
Possible causes
- The destination country has inbound calling restrictions.
- The number type is blocked by Aircall by default. See the section Number is blocked when calling overseas.
- The number is invalid or inactive.
Steps you can take
- Call the number from an Aircall number in the same country.
- Call the number from an Aircall number in a different country.
- Call the number from a non Aircall phone.
If it fails from all phones, the number is likely invalid or out of service.
Tip: Make note of the exact error message you hear. This helps Support quickly identify the root cause.
Understanding the results
- If the call works from another Aircall number, use that number or a similar one for future calls.
- If it fails from all Aircall and non Aircall numbers, the number may be inactive or invalid.
- If you continue hearing “This number is forbidden,” contact Support or your Account Manager to enable the required features.
4. When and how to contact Support
Contact Aircall Support or your Account Manager when:
- A destination appears blocked by contract or feature settings.
- A number needs to be whitelisted by a carrier.
- A Thai number must be moved to an outbound capable carrier.
- Troubleshooting confirms the issue is not caused by dialing format or local rules.
When submitting a request, include:
- The number you are trying to reach
- The Aircall number you dialed from
- The exact error message
- Call samples and call UUIDs
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