API issue when editing order in opencart admin - opencart2.x

Question

Afternoon all,
I've got an issue when trying to change the status of an order (from pending to complete etc...) in the admin section.
A warning appears saying
Warning: You do not have permission to access the API!
if i have add my IP to the API IP address section it's working fine
the fields are all in red and the continue button doesn't work.
A similar thing happens if I view an order instead and try to add a new status to the order history.
I've seen this problem mentioned a few times in other posts but, afaik, without any satisfactory answer.
I'm using Opencart 2.0.3.1 and I'm logged in as an administrator and the administrator user group has all Access and Modify permissions enabled.
There is the default API user set up in System > Users > API and I also added (and then removed) another one but I was not sure what to do once I had created a new API user with a username and generated password.
There are no other problems on the site but, despite trying just about all the suggestions in the other forum posts, I can't edit the existing orders from the admin section.

Answer 1

Check this page out with a list of fixes for this issue: http://www.randemsystems.com/support/opencart/api-problems-what-you-need-to-know/msg6218/#msg6218
As far as I know, this issue is resolved in OC v2.1x onwards

Answer 2

The problem is that you need an API user with a valid IP address.
Go to System > Users > API.
Either modify the Default API by adding your IP address in the second tab, or just create a new API.
After that you should make sure the API is selected in System > Settings > Edit > Option > API User.
Click save, refresh and try adding order history again.
I tried the same thing and didn’t have permission to access the API when attempting to add order history. Follow the steps and it should work for you, as it worked for me.

Answer 3

I know it's late, but after trying everything and not getting it working, I deleted everything here /system/storage/cache. It solved the problem.

Answer 4

It works perfect for me .
1- Open index.php file of root directory
2- add the following after define('version',x.x.x.x);
if ($_SERVER["HTTP_CF_CONNECTING_IP"])
{
$_SERVER["REMOTE_ADDR"] = $_SERVER["HTTP_CF_CONNECTING_IP"];
}