Hi Ronak,
I’m sorry you’re not able to create tickets, but I’ll be happy to help you figure out what’s going on!
First, can you try updating to the latest versions:
The Events Calendar – 4.6.7
Event Tickets – 4.6.2
Event Tickets Plus – 4.6.2
If you don’t see a prompt to update in the Plugins section of your Dashboard, you can do so manually by following these instructions.
If this is still occurring, the next step would be to test for conflicts with your theme and other plugins by following these instructions. If you prefer not to do this on your live site, the free WP Staging plugin will let you create a quick copy of your live site that you can use for testing.
Let me know what you find!
Thanks,
Jennifer