I have no domain. I am not admin of anything. All I want to do is send an email from a zohomail.eu address, using the Zoho android app, with all settings as default.
I do not use Office 365, or EOP, or Outlook, and I have no domain or domain registrar.
I am getting an SPF validation error, with this additional text: "Status code: 550 5.7.23
This error occurs when Sender Policy Framework (SPF) validation for the sender's domain fails. If you're the sender's email admin, make sure the SPF records for your domain at your domain registrar are set up correctly. Office 365 supports only one SPF record (a TXT record that defines SPF) for your domain. Include the following domain name: spf.protection.outlook.com. If you have a hybrid configuration (some mailboxes in the cloud, and some mailboxes on premises) or if you're an Exchange Online Protection standalone customer, add the outbound IP address of your on-premises servers to the TXT record."