Getting a 503 error after upgrading to 5.0.3 when trying to access the admin site

I recently upgraded Openfire Server from 4.8.1 to 5.0.3. Since then, I cannot access the admin side whether it is on the network or from the host server itself. I have gone to the openfire.xml file and verified that the line 127.0.0.1 is deleted. Here is a screenshot of the error I get:

Spark is still working on every machine on the network, I just can’t access the admin side.

Any help is greatly appreciated! I am new to working on servers and new to Openfire. Thanks!