1004 error when setting up 123 Reg Mailbox 2

[ers]

123 Reg has updated our mailboxes to their new platform and sent over the details to update our MX records on Cloudflare to point to their new server.

When I try to set up the first MX record they sent over:

Type: MX
DNS Entry: @
Priority: 0
TTL: 3600
Destination/Target: smtp‌.‌secureserver‌.‌net

as

Type:MX
Name (required): @
Mail server (required): smtp‌.‌secureserver‌.‌net
TTL: 1 hr
Priority (required):0

In Cloudflare, I get the error: DNS Validation Error (Code: 1004) Change the content of your MX record to be a hostname (and not an IP address).

I don’t understand this as I haven’t put in an IP address.

[ers]

For anyone with the same problem, the issue was that the email from 123-reg had ‘zero-width non joiner’ characters in the destination/target. The solution was to type out the domain rather than copy and paste it from their email.