daily tests failing: SimplesamlphpAuthManagerTest has CriticalConfigurationError

Drupal\Tests\simplesamlphp_auth\Unit\Service\SimplesamlphpAuthManagerTest
exception: [Other] Line 0 of sites/default/files/simpletest/phpunit-3.xml:
PHPunit Test failed to complete; Error: PHPUnit 4.8.36 by Sebastian Bergmann and contributors.

Testing Drupal\Tests\simplesamlphp_auth\Unit\Service\SimplesamlphpAuthManagerTest
E.......

Time: 255 ms, Memory: 5.50MB

There was 1 error:

1) Drupal\Tests\simplesamlphp_auth\Unit\Service\SimplesamlphpAuthManagerTest::testIsActivated
SimpleSAML\Error\CriticalConfigurationError: The configuration (config/config.php) is invalid: Missing configuration file

/var/www/html/vendor/simplesamlphp/simplesamlphp/lib/SimpleSAML/Error/CriticalConfigurationError.php:77
/var/www/html/vendor/simplesamlphp/simplesamlphp/lib/SimpleSAML/Configuration.php:343
/var/www/html/vendor/simplesamlphp/simplesamlphp/lib/SimpleSAML/Logger.php:362
/var/www/html/vendor/simplesamlphp/simplesamlphp/lib/SimpleSAML/Logger.php:402
/var/www/html/vendor/simplesamlphp/simplesamlphp/lib/SimpleSAML/Logger.php:178
/var/www/html/vendor/simplesamlphp/simplesamlphp/lib/_autoload_modules.php:70
/var/www/html/core/tests/Drupal/Tests/PhpunitCompatibilityTrait.php:91
/var/www/html/modules/contrib/simplesamlphp_auth/tests/src/Unit/Service/SimplesamlphpAuthManagerTest.php:75

FAILURES!
Tests: 8, Assertions: 13, Errors: 1.