It is not an error, but a common step while working towards stronger methods of protecting against spoofing. The warning reminds you that your published record, while still useful to opt into receiving reports, is not asking recipients to act on a more restrictive policy yet.
It is perfectly fine to continue with that record until you have gathered enough data to confidently request enforcement. At some point you probably want to change your policy to p=reject
. The decision you are making depends less on how much spoofed mail you see, but more specifically on whether you know that all legitimate senders for that domain are known to you and correctly configured to appear authorized to recipients.
If you actually send significant mail volume for that domain from multiple systems, you probably do not want to read the incoming reports yourself, but have them sent towards some automated processing/visualization/notification system. The site you linked does offer such system as a commercial service, multiple such services exist and usually work by buying a subscription and configuring them or forwarding to them as the report target.