If an error occurs when setting up the email for the ATS emails, it might be due to the length which sometimes happens on the DKIM. You would need to split it as shown below:
https://stackoverflow.com/questions/36688278/unable-to-setup-dkim-txt-value-as-dns-record
📌Note: It can take up to 48 hours once added for this to show as green and to be verified, depending on the domain provider.