Missing SPF Flags on nextcloud.com

How it was found

Hello NextCloud

Details i just test your domain which is nextcloud.com and i surprised that i can send a legit email to a user.

Impact

Attacker can use this to send a Legit Email to the Victim and attacker can send a Malicious Web Links and Phishing Sites.

Video Proof of Concept

https://mega.nz/#!rtQHxQqa!sd4U7XHvCGvBS-WJMxfzm-NiJVt8ADrxQI3Wwx81raw

Reference (Similar Reports):: #54779 & #57736

Let me know if i miss something. Looking forward to it's fix. Best Regards, @ph_spade