Symptom
After applying the 8.2.0 update, you may observe a TypeError error message when provisioning Plesk services:
TypeError: Argument 1 passed to WHMCS\Service\Service::removeMxRecords() must be of the type array or null, string given, called in /path/to/whmcs/vendor/whmcs/whmcs-foundation/lib/MarketConnect/Services/OX.php
or
TypeError: Return value of Plesk_Api::_escapeValue() must be of the type string, null returned in /path/to/whmcs/modules/servers/plesk/lib/Plesk/Api.php:0
Solution
Please apply the 8.2.1 Maintenance Release via the Utilities > Update WHMCS page.
Hotfix
A hotfix has been created for 8.2.0 only to correct this behaviour.
The End! should you have any inquiries, we encourage you to reach out to the Vercaa Support Center without hesitation.