office emailing + cpa offer

hello everyone,

i got edu logins for office365 so i used it as an smtp,
i extracted some emails and validate them with netflix vm software (to get only interested peoples in the streaming niche)
and i started sending out with the smtp for the cpa letter that tell them to get a free netflix access (btw i sendout only to free emails)
but i'm getting my email rejected from the office while sending, any help or suggestion please ?

i'ill update here every step i do

Show the error log to get a proper answer.

Thanks

Error log means you will get one code from the SMTP log. It looks like 512.18 or something like that
Based on the image check below possible conditions.
1) MX records on SMTP sender
2) SPF record on SMTP sender
3) Domain spamhaus stats
4) valid DKIM key.

Good luck