Domain Management TypeError: Argument 1 passed to str_starts_with() must be of the type string Errors

Symptom

After updating to WHMCS v8.6.0, users of the ResellerClub registrar module may encounter a TypeError when accessing a client's Domains tab in the admin area, when that account contains a domain transfer:

TypeError: Argument 1 passed to str_starts_with() must be of the type string, null given

Cause

The raaVerificationStartTime and endtime values returned by the ResellerClub API are null or non-numeric for this domain, when WHMCS expects to receive a timestamp.

Solution

Apply the 8.6.1 Maintenance Release via Utilities > Update WHMCS.

Hotfix

We have created a hotfix for WHMCS 8.6.0 to resolve the error:

https://whmcs.community/files/file/181-core-18272-correct-fatal-php-error-after-performing-a-resellerclub-transfer-in-the-admin-area/

Workaround

Switch your hosting environment to PHP 8.1.

For more information see How to Use WHMCS with PHP 8.1.