Hi @PMor 
@Bastien_Siebman has developed a great tool to check all custom fields in your Organization: iDO Tools - Improve Asana with our tools and automations if you want to double check if your custom field still lives in your Org. If it doesn’t, our support team should be able to assist you. you can reach out to them following these steps: https://forum.asana.com/t/how-do-i-contact-support/19057/7?u=marie. In order to speed up things, I would recommend providing our support team with the following info:
- Name of the Custom Fields
- Name of the Organization or Workspace the custom field used to live in
If there is anything else we can help with, feel free to reach out in the Forum, we’ll be more than happy to help!