# When submitting a contact the phonenumber is deemed invalid.

WHMCS and our plugin attempt to format your input in such a way that it can be used by our API and other external systems. Sometimes this conflicts with your usual way of working.

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**131- Invalid telephone country code!**

The most common cause of a phone number being judged as invalid is because users leave the phone number field empty, however this is a mandatory field in Openprovider.   
Another common cause of this error is when users add a country code to the number. WHMCS does this as well (using the country of the contact to get the country code) and this results in +3131 making it an invalid country code.

**Solution**: Review the phone number of domain contacts and add/correct it.

#### **133 - Invalid telephone region code number!**

Area/region code is part of the phone number (excluding leading zero). Incomplete phone number or invalid format in phone number can cause this error.

**Solution:** Review the phone number of domain contacts and correct it. If you have the following option disabled in WHMCS Admin Dashboard > **Configuration** > **System Settings** > **General Settings > Localisation** (tab), specify the phone number in a format like +XXX.XXXXXXX having dot (.) symbol included as a delimiter.

![embedded-image-jtyidswj.png](https://openprovider.help/uploads/images/gallery/2026-08/embedded-image-jtyidswj.png)

By default, WHMCS uses the following phone number format, automatically prefixing the number with the international country dialing code for the client’s selected country:

\+ \[Country Code\] . \[Phone Number\]

#### **135 - Invalid telephone subscribers number!**

Incomplete phone number, invalid format or invalid characters in phone number can cause this error.

**Solution:** Review the phone number of domain contacts and correct it.

If the cause is not clear, feel free to [contact our support department](https://openprovider.help/books/quick-start/page/contact-openprovider-support). They can check the logs and see what is being sent to the API and possibly hint you in the right direction.