I transferred my domain to Cloud Flare for its domain registrar. Never had an issue sending email to gmail accounts until I transferred the domain. I added the following TXT record as per my web host
v=spf1 a:5817.submission.antispamcloud.com a:release.antispamcloud.com ~all
Still getting 550 High probability of spam when sending some, but not all emails to gmail.
Thanks : )