Gmail is bouncing emails sent by sendmail. The from address is name@mydomain and I've set up an SPF DNS record for mydomain which looks like

v=spf1 a a:aremiti36.vps.bitfolk.com ip6:2001:ba8:1f1:f09e::2 ~all

the domain and https://www.dmarcanalyzer.com/spf/checker finds it OK

but i'm still getting emails bounced:

kit.wallace@gmail.com

SMTP error from remote mail server after end of data:
host gmail-smtp-in.l.google.com [2a00:1450:400c:c06::1a]:
550-5.7.26 This message does not pass authentication checks (SPF and DKIM both
550-5.7.26 do not pass). SPF check for [aremiti36.vps.bitfolk.com] does not
550-5.7.26 pass with ip: [2001:ba8:1f1:f09e::2].To best protect our users from
550-5.7.26 spam, the message has been blocked. Please visit

name@mydomain is redirected to kit.wallace@gmail.com so I'm not sure gmail is even looking at mydomain's DNS record anyway

Basically I don't know what I'm doing and in need help!

Chris