Hi @kimarkf01
I’m sorry but a PHP notice is not a cause of a 503 error, as I let you know, a PHP notice is just as a notice for developers, but if does not causes issues in any way, for that I recommended you to investigate from where this 503 error comes with your hosting provider
You are seeing it because you have your server configured as a development environment which is NOT recommended if your site is live and in production
Please, contact with your hosting provider to stop logging PHP notices and only log PHP errors, because storing PHP notices will overload your server logs and also to meet what is causing this 503 error
Best regards