If payment status is marked as Received after successful payment you have to change "Automatic Payment Status" option to Order Paid.
You will find this option in Tickera > Settings > Payment Gateways > Free Orders Settings
In case that orders are pending (Order status is Received) after successful payment make sure to set up the following parameters in your PayPal account:
1. Go to Profile and Settings
2. My selling tools
3. Credit card statement name
4. Allow payments sent to me in a currency I do not hold – Set to: Yes, accept and convert them to (your currency)
Set up Auto Return go to your PayPal:
1. Log in and click the Profile subtab under My Account.
2. Click the Website Payment Preferences link under Selling Preferences.
3. Click the On radio button to enable Auto Return.
4. Enter the Return URL: http://www.yoursite.com
Also you have to:
1. Go to Profile and Settings
2. My selling tools
3. Website preferences
4.Payment Data Transfer (optional): has to be set – Off
IPN errors can also affect on a Order Status. So if you see IPN errors, go to Tickera > Settings > Payment Gateways > PayPal Standard and set Yes for "Ignore IPN errors" option.