I got it working with Cloudflare
add a TXT record
under name, enter (without quotes) '@'
under key, enter (without quotes) 'v=spf1 a mx include:spf.migadu.com ~all'
You must delete all other SPF TXT entries (so if you were previously on google hosted, delete the Google SPF record.
You must delete all other SPF TXT entries (so if you were previously on google hosted, delete the Google SPF record.