Unable to retrieve creatives from DCM - google-apis-explorer

Question

I wrote a script that pulls information about creatives from DCM function described here: https://developers.google.com/doubleclick-advertisers/v3.2/creatives/list
It worked fine for last couple month, however, starting a couple days ago, I began getting the following error:
PHP Fatal error: Uncaught Google_Service_Exception: {
"error": {
"errors": [
{
"domain": "global",
"reason": "backendError",
"message": "Backend Error"
}
],
"code": 500,
"message": "Backend Error"
}
}
in /var/www/html/dcm/vendor/google/apiclient/src/Google/Http/REST.php:118
Stack trace:
#0 /var/www/html/dcm/vendor/google/apiclient/src/Google/Http/REST.php(94): Google_Http_REST::decodeHttpResponse(Object(GuzzleHttp\Psr7\Response), Object(GuzzleHttp\Psr7\Request), 'Google_Service_...')
#1 /var/www/html/dcm/vendor/google/apiclient/src/Google/Task/Runner.php(181): Google_Http_REST::doExecute(Object(GuzzleHttp\Client), Object(GuzzleHttp\Psr7\Request), 'Google_Service_...')
#2 /var/www/html/dcm/vendor/google/apiclient/src/Google/Http/REST.php(58): Google_Task_Runner->run()
#3 /var/www/html/dcm/vendor/google/apiclient/src/Google/Client.php(779): Google_Http_REST::execute(Object(GuzzleHttp\Client), Object(GuzzleHttp\Psr7\Request), 'Google_Service_...', Array)
#4 /var/www/html/dcm/ in /var/www/html/dcm/vendor/google/apiclient/src/Google/Http/REST.php on line 118
I have tried using "Try this API" feature to see if anything has changed, and after logging in with Oauth2 I am receiving the following error while trying to list creatives:
{
"error": {
"errors": [
{
"domain": "global",
"reason": "backendError",
"message": "Backend Error"
}
],
"code": 500,
"message": "Backend Error"
}
}
Is there something that I need to change on my end, or is this a global issue?