Critical error while displaying hashtag

Hi

I have a problem with displaying hashtag feed. I have business account which I assign to Social Slider. Then I create widget with displaying hashtag posts. I copy shortcode and paste it in elementor editor. When I do it, on my page there is a critical error message, site is deformed, no Social Slider content is visible.
If I switch feed content to display posts on accounts, everything is fine. Problem is only with hashtag.

WordPress ver 5.7.2
Plugin: Social Slider Widget (ver 1.9.5)
PHP ver: 7.2.34

Error dump:

Error of type E_ERROR corrupted by line 1990 of file: /home/[server_name]/domains/[domain_name.com]/public_html/wp-content/plugins/instagram-slider-widget/includes/class-wis_instagram_slider.php. Error message: Uncaught Error: Call to undefined function array_key_first() in /home/[server_name]/domains/[domain_name.com]/public_html/wp-content/plugins/instagram-slider-widget/includes/class-wis_instagram_slider.php:1990
Stack trace:
#0 /home/[server_name]/domains/[domain_name.com]/public_html/wp-content/plugins/instagram-slider-widget/includes/class-wis_instagram_slider.php(1331): WIS_InstagramSlider->getAccountForHashtag()
#1 /home/[server_name]/domains/[domain_name.com]/public_html/wp-content/plugins/instagram-slider-widget/includes/class-wis_instagram_slider.php(804): WIS_InstagramSlider->instagram_data(Array, 5, 8, false)
#2 /home/[server_name]/domains/[domain_name.com]/public_html/wp-content/plugins/instagram-slider-widget/includes/class-wis_instagram_slider.php(454): WIS_InstagramSlider->display_images(Array)
#3 /home/[server_name]/domains/[domain_name.com]/public_html/wp-includes/shortcodes.php(343): WIS_InstagramSlider->shortcode(Array, '', 'jr_instagram')
#4 [internal function]: do_shortcode_tag(Array)
#5 /home/[server_name]/domains/late

What can be a problem?
I tried to reinstall plugin and reconnect bussiness account.