Advanced DNS Editor rejects valid CNAME host names with underscores/dots (e.g. for DKIM records)

Hi, I'm trying to add several CNAME records to concordsoapcompany.com through the Advanced DNS Editing page (Domains > Advanced DNS settings) in order to set up email authentication (DKIM) required by Shopify. The host names Shopify requires include underscores and dots, for example: z8p._domainkey, pdk1._domainkey.mailer6fq. When I try to submit, I get this message: "Please enter a valid host name, which can either be an alpha-numeric string (like 'abc123'), or * for your CNAME Records." This blocks me from adding standard DKIM CNAME records. I was able to add two simpler CNAME records (mailerz8p, mailer6fq) without issue, but the four records with underscores/dots in the host name are rejected. On a separate attempt I also received a "partners are experiencing some technical difficulties" error when submitting. Could you please either: (1) manually add the following 4 CNAME records to my domain's DNS on your end, or (2) let me know if there's a different way to submit host names with underscores/dots through Advanced DNS Editing? Records needed: Host: z8p._domainkey -> dkim1.2c8ff658bf70.p744.email.myshopify.com Host: z8p2._domainkey -> dkim2.2c8ff658bf70.p744.email.myshopify.com Host: pdk1._domainkey.mailer6fq -> dkim3.cd98b20545e1.p85.email.myshopify.com Host: pdk2._domainkey.mailer6fq -> dkim4.cd98b20545e1.p85.email.myshopify.com Thank you!