I manage my DNS from namecheap, which namecheap asks me to add a record A to manage the PTR of the emails, which leaves me without Record A space to add the vercel one, I do not have the option of making a subdomain or using the nameserver Vercel, what solution would I have?
Hey . I know configuring DNS records can sometime be tricky, and it sounds like you have an unusual setup for your email and domain.
Email usually requires MX and TXT records. Using an A record for email is not typical for the exact reason that you ran into – only one A record is allowed for a domain and it's needed to point traffic from your address (e.g. example.com) to the appropriate IP address (e.g. 76.76.21.21). That's the convention for just about everything on the internet.
It looks like Namecheap's email setup only requires MX and TXT records along with some optional SRV and CNAME records: https://www.namecheap.com/support/knowledgebase/article.aspx/1338/2176/how-to-set-up-namecheap-private-email-dns-records-for-domains-on-namecheap-basicpremium-nameservers/#manual_setup
If you need help with Namecheap email setup, I recommend reaching out to the Namecheap support team. They have more info about your account and are familiar with how their products should be configured.