I don't have this lens so I'm going to make general suggestions which may be more stuff you've tried. For this type of photo, you'll need a lot of light. Noon at the height of summer in a tropical location is a good start.
The light is needed so you can have a good shutter speed, like 1/125s or 1/250, and a small aperture like f11 or f16. You'll probably also need to go to ISO 400 or more. Those settings sound extreme for regular photography, but for macro photography you need them for decent depth of field and to reduce the possibility of camera shake or subject movement. With high magnification at close distances, your depth of field at f5.6 or f8 will be way too small.
If you don't have that much light, a tripod can help. Sometimes it is tricky getting a tripod to hold the camera in the right place for your subject, but the extra stability is very useful. Remember to turn SR off on a tripod. It can be much easier to move the camera than refocus. Autofocus might not be able to get the exact point of focus you want, so you might try manual focus. Wind can easily ruin a macro shot by moving the subject, causing both motion blur and changing where your point of focus is. So make sure it's a calm day at noon in the summer in the tropics.
It will probably take some experimental pictures to figure out your problem. Check your settings first, and try my settings above to see if they work better. Then if you can post a photo with your settings and details, we can help more.