E error

Hi,
I installed the plugin to try it out but got a fatal error on the writing settings page:

An error of type E_ERROR was caused in line 307 of the file .../wp-content/plugins/wp-bitly/includes/class-wp-bitly-settings.php. Error message: Uncaught TypeError: count(): Argument #1 ($var) must be of type Countable|array, null given in .../wp-content/plugins/wp-bitly/includes/class-wp-bitly-settings.php:307
Stack trace:
...public_html/wp-content/plugins/wp-bitly/includes/class-wp-bitly-settings.php(176): Wp_Bitly_Settings->get_group_options()
.../public_html/wp-admin/includes/template.php(1737): _f_settings_field_default_group()
.../public_html/wp-admin/includes/template.php(1695): do_settings_fields()
.../public_html/wp-admin/options-writing.php(233): do_settings_sections()
#4 {main}
  thrown

So I disabled the plugin — but it will NOT delete.