Issue problem with mail

[zakaria]

Server operating system version

Debian 10.13

Plesk version and microupdate number

Plesk Obsidian 18.0.52 Update #3

hello, hope everyone is doing well.

I'm trying to configure mail in Plesk, with a domain that's configured in GoDaddy.
every time I try to send an email to an external address it gives me a smtp error 550 5.1.1
and when I send it internally it says it was sent successfully but when I check I find nothing

the DNS records I have in Plesk are:
example.com, NS, ns1.example.com
example.com, NS, ns2.example.com
example.com, MX (10), webmail.example.com
example.com, MX (10), mail.example.com
ns1.example.com, A, Plesk server IP
ns2.example.com, A, Plesk server IP
webmail.example.com, A, Plesk server IP
mail.example.com, A, Plesk server IP

the DNS records I have in GoDaddy are:
mail.example.com, A, Plesk server IP
webmail.example.com, A, Plesk server IP
NS @ ns05.domaincontrol.com. created by GoDaddy can't be edited or removed.
NS @ ns06.domaincontrol.com. created by GoDaddy can't be edited or removed.
NS @ ns1.example.com
NS @ ns2.example.com
there are also and not sure if these cause a conflict.
NS emailing ns1.sendinblue.com
NS emailing ns2.sendinblue.com
and
MX @ mail.example.com. (Priority: 10)
they all resolve to the correct address.