Error #503F. Worst error message ever?

Hi ​@ComeHitherDesign,

Sorry to hear that you’re experiencing this issue and I understand how frustrating the message can be. Adding to the suggestions shared by the expert, if the issue still persists, please try resetting the InDesign preferences manually by following the steps shown in this article: https://helpx.adobe.com/indesign/using/setting-preferences.html

Also, please try using Publish Online from a different network, like your phone’s hotspot, and temporarily disable the firewall if it is enabled. Additionally, kindly check if the required endpoints mentioned in this article are accessible on your network: https://helpx.adobe.com/enterprise/kb/network-endpoints.html

Please let us know how it goes or if you notice any changes after trying the above steps, so we can continue investigating this further with you.

Abhishek

<humor>Why don’t you try again sometime?</humor>