Battery failing

I have a solar security camera which is about 6 months old and today it is advising me that it’s down to 26%. The other solar camera I have is fully charged so it’s not a problem with light. A code is on the app P3-17 which I can’t find what it means. I don’t know if the battery is failing or the panel is not charging. It doesn’t get much use so my thoughts are towards a failed battery.