Can someone please tell me why these photos aren't accepted

BTW, as it helps to use a high quality camera, it is not exactly the camera that takes the pictures. It's the photographer who needs to use the correct settings and it's the image editor who needs to correct the image. Mostly you need to fill in both roles.

Hi @naturestorypics 

When zoomed I noticed that the first 3 files are out of focus and with chromatic and compression noise. The next file has shallow depth of field and with chromatic noise.

Out of focus and underexposed

Compression and chromatic noise

Chromatic noise

It's a good thing to use a good quality camera. However, it's also a good thing to learn the skills of adjusting your camera to take sharp photos with correct exposure. Having correct exposure will reduce noise. Even if you have the skill to capture the best quality photos, it's essential to include post processing to correct camera error such as noise.

Best wishes

Jacquelin

The second image also has spots in the sky.

In the third image, the depth of field is too shallow, causing most of the image to be out of focus.

In the monkey image, the texture of the fur has been crushed - not sure if this is a DOF issue...

The flower in the first image is not in sharp focus and there is debris, probably lens spots or sensor spots in the sky.

Your first: 

you have sever dust patterns on the picture.

Your second:

Sensor dust, compression artefacts and a lack of sharpness and detail.

Your third: compression artefacts and a lack of dof.

Your last: besides being overexposed, there is a lack of detail, may be from severe noise reduction or from a software portrait mode: 

The top three lack focus. Not sure about the monkey.