Where did it go wrong and I got this result?

I was doing a 5 sample analysis. I’m pretty sure the result shouldn’t look like this, but I have no idea where it got wrong. I’m posting taxa barplot and denoising stats so you could take a look.
I need to know if this is about computational problem or something went wrong in sample preparation process.
If you need to see any other file, I can post it, too. I need help asap.
(This is the first time I upload something, and I can’t preview the post, so I don’t know how it will look like. If it is bad, please excuse me :))

Thank you for your attention dear Qiimers…

You’re going to have to give some more information about the samples, because without knowing what you expect it to look like, it’s hard to say what went wrong (if anything).

The only obvious thing I can see is that your barplot has only 4 samples, not 5; presumably the last (OK1) didn’t have enough reads to be included. You also seem to have lost a lot (~80%) of your reads in the first filtering step; not sure if that might be a problem.

What were these 5 samples? It looks like OK2 & OK3 are one sample type, and OK4 and OK5 are another. Is that the case, or are these supposed to be 5 similar replicates?