Website crash on Plugin activation

Hello,

The plugin description sounds really awesome, so I’ve wanted to try out this plugin, but isn’t working.

Here’s the error message I get when I activate the plugin (as a screenshot):
https://d.pr/free/i/au9H4N

The message is the following:

===
Fatal error: Uncaught Error: Call to a member function wp_rewrite_rules() on null in /home/satoshi/public_html/wp-includes/rewrite.php:527 Stack trace: #0 /home/satoshi/public_html/wp-content/plugins/ranking-and-competitor-tracking/class.ranking-and-competitor-tracking.php(69): url_to_postid(‘https://satoshi…’) #1 /home/satoshi/public_html/wp-content/plugins/ranking-and-competitor-tracking/ranking-and-competitor-tracking.php(38): hub_ract_metrics->__construct(‘/home/satoshi/p…’) #2 /home/satoshi/public_html/wp-settings.php(360): include_once(‘/home/satoshi/p…’) #3 /home/satoshi/public_html/wp-config.php(90): require_once(‘/home/satoshi/p…’) #4 /home/satoshi/public_html/wp-load.php(37): require_once(‘/home/satoshi/p…’) #5 /home/satoshi/public_html/wp-admin/admin.php(34): require_once(‘/home/satoshi/p…’) #6 /home/satoshi/public_html/wp-admin/plugins.php(10): require_once(‘/home/satoshi/p…’) #7 {main} thrown in /home/satoshi/public_html/wp-includes/rewrite.php on line 527
===

Can you look into this further?
Here’s the info I saw from other pos. Let me answer them to make it easier for you to look into this.

What version of PHP was installed on your server?
7.2

What version of WordPress were you running?
5.3

Was there a conflict with some other plugin?
I’ve deactivate all my other plugins but still acts the same.

Also, another question.
To use your plugin, do I need to register an account at your website?

Looking forward to your reply.

Thanks,
Satoshi O.