How to troubleshoot if checkout rate is not working in woocom plugin

1. A valid Auspost / Aramex / Couriers Please App account is added

2. Joovii shipping is added to the proper shipping zone

3. Product weight is added

4. A valid customer address is added in the checkout

5. Check the following server settings to prevent curl execution time out

max_execution_time = 60

max_input_time = 300

memory_limit = 256M

post_max_size = 128M

upload_max_size = 128M