I developed simple provisioning module for WHMCS. This module worked fine on version 6.2.2. But it raises 'InvalidArgumentException' when the module making a call to localAPI() with 'getclientsproducts' as function name.
http://docs.whmcs.com/API:Get_Clients_Products#External_API
Fatal error: Uncaught exception 'InvalidArgumentException' with message 'Invalid "{"language":"","fullName":" ","countryName":null}" locale.' in /usr/local/www/sandiloka.com/html/members/vendor/symfony/translation/Symfony/Component/Translation/Translator.php:437 Stack trace: #0 /usr/local/www/sandiloka.com/html/members/vendor/symfony/translation/Symfony/Component/Translation/Translator.php(247): Symfony\Component\Translation\Translator->assertValidLocale(Object(WHMCS\User\Client)) #1 /usr/local/www/sandiloka.com/html/members/vendor/symfony/translation/Symfony/Component/Translation/Translator.php(210): Symfony\Component\Translation\Translator->getCatalogue(Object(WHMCS\User\Client)) #2 /usr/local/www/sandiloka.com/html/members/vendor/illuminate/support/Illuminate/Support/Facades/Facade.php(217): Symfony\Component\Translation\Translator->trans('custom_field.72...', Array, 'dynamicMessages', Object(WHMCS\User\Client)) #3 /usr/local/www/sandiloka.com/html/members/includes/classes/WHMCS/CustomField.php(0): Illuminate\Support\F in /usr/local/www/sandiloka.com/html/members/includes/classes/WHMCS/Terminus.php on line 0
I have reported this issue to WHMCS via ticket. But those guys still cannot address the problem and blame my code. Please check the stack trace, you will see the exceptions raises by their code.