If you have a web hosting plan with Mynymbox but want to use Protonmail for your emails, follow the steps below.
1. In DirectAdmin - "ACCOUNT MANAGER" go to "DNS Management"
2. Here you have to delete the current DNS records for our email server - mail.YOURDOMAIN.com and the .TXT record for the SPF with "mailbaby".

3. Login into Protonmail, click on the wheel, "All Settings" and click on "Domains Names"
4. Add your Domain Name which you want to use for Protonmail
5. Click all the steps through in Protonmail and configure the DNS Records in DirectAdmin - see below
Verfiy
Record Type: TXT
Name: leave it empty
TTL: leave it empty
Value: protonmail-verification=XXXX
Addresses
Configure your email addresses in Protonmali, nothing to do in DirectAdmin
MX
Record Type: MX
Name: leave it empty
TTL: leave it empty
Value: 10 mail.protonmail.ch
Record Type: MX
Name: leave it empty
TTL: leave it empty
Value: 20 mailsec.protonmail.ch
SPF
Record Type: TXT
Name: leave it empty
TTL: leave it empty
Value: v=spf1 include:_spf.protonmail.ch ~all
DKIM
Record Type: CNAME
Name: protonmail._domainkey
TTL: leave it empty
Value: protonmail.domainkey.XXX
Record Type: CNAME
Name: protonmail2._domainkey
TTL: leave it empty
Value: protonmail2.domainkey.XXX
Record Type: CNAME
Name: protonmail3._domainkey
TTL: leave it empty
Value: protonmail3.domainkey.XXX
DMARC
Record Type: TXT
Name: _dmarc
TTL: leave it empty
Value: v=DMARC1; p=quarantine
Once all records are added you can use Protonmali as soon as all checkmarks are green.