The playback feature (from the microSD card) is either “not user-friendly enough yet”, OR, is buggy, OR, both. However, with some patience, and/or some trial-and-error, it nearly always delivers for me. This explains why I continue to buy these. I project that with time, wyzecam developers make these more robust.
In some cases, the microSD card needs to be re-formatted, OR, can be “bricked”, especially if it is not a high-performance card. SanDisk even says they won’t warranty their normal cards if used in high use scenarios, such as security cams.