I just submitted my common app for UNC EA but the ACT website is under maintenance and I am unable to send my scores right now. What should I do about this?

What else can you do but wait for it to be available again. If you worry the score report may be late and has a less desirable SAT score, you may submit that to make your application complete by deadline to buy some time. Test scores orders should be placed at least 2 weeks before application deadline if the scores are available already. Never wait till the last few days. Indeed, it is better to submit the application a couple weeks before deadline too if you want a chance to track for missing document before deadline.