Using New Outlook on Windows for personal email, calendar, and contact management
Your domain doesn't have SPF and DMARC records:
https://easydmarc.com/tools/spf-lookup?domain=ppshr.co.uk https://easydmarc.com/tools/dmarc-lookup?domain=ppshr.co.uk
If you have an IT person, have them create all 3 records, SPF, DMARC and DKIM. This article should help: https://learn.microsoft.com/en-us/microsoft-365/security/office-365-security/email-authentication-spf-configure?view=o365-worldwide