To ensure you do not delete browser cookies, update your browser settings as follows (if you are using Google Chrome scroll down for instructions):
1. Open Firefox.
2. Click the Open Menu option
3. Click Options.
4. Click Privacy.
5. From the Firefox will drop-down list, select Remember History.
6. Click Clear your recent history.
7. Select the time range for which you want to clear history.
8. Expand Details.
9. Deselect the Cookies checkbox.
10. Click Clear Now.
11. Click Advanced.
12. Click the Network tab.
13. Select the Override automatic cache management checkbox and set the cache limit to 1024 MB.
For Google Chrome:
If you are using Google Chrome, you must first check if the Flash Player is always allowed to run (select setting: To enable Flash Player to always run). Follows the steps mentioned in the following link:
If the problem persists, you must clear your browsing data as follows:
1. Open Google Chrome.
2. Click the Customize and control Google Chrome option on the top-right.
3. Click Settings > History > Clear browsing data.
4. Clear the Cookies and other site and other site plugin data checkbox.
5. Click Clear browsing data.
Read instructions in https://support.apple.com/en-in/HT201265