XF 2.3 indexnow server error

I'm getting server errors on one site and not the other. Something I'm missing in the setup?

• ErrorException: IndexNow error: [500] An unexpected error occurred. Please try again later.
• src/XF/Error.php:82

Stack trace

#0 src/XF.php(266): XF\Error->logError('IndexNow error:...', false)
#1 src/XF/IndexNow/Api.php(86): XF::logError('IndexNow error:...')
#2 src/XF/IndexNow/Api.php(34): XF\IndexNow\Api->request('/?key=XXXXXXXXX...', Array, 'IndexNow error:...')
#3 src/XF/Job/ContentIndexNow.php(84): XF\IndexNow\Api->index('https://sneaker...')
#4 src/XF/Job/Manager.php(275): XF\Job\ContentIndexNow->run(4.4372)
#5 src/XF/Job/Manager.php(205): XF\Job\Manager->runJobInternal(Array, 4.4372)
#6 src/XF/Job/Manager.php(89): XF\Job\Manager->runJobEntry(Array, 4.4372)
#7 job.php(46): XF\Job\Manager->runQueue(false, 8)
#8 {main}