Loading failed /js/datepicker_language/bootstrap-datetimepicker..js?ver=2016-02

Hey guys, I seem to have a little problem with the specific script.
I’m getting a lot of 404 hits from the following script:

Loading failed for the <script> with source “https://www.dominion-nails.com/wp-content/plugins/salon-booking-system/js/datepicker_language/bootstrap-datetimepicker..js?ver=2016-02-16”.

Screenshot: https://ibb.co/cTPJFGp

My domain is multilingual. The main language of the website is English and second language is Czech.

I tried re-uploading the complete plugin multiple times but it didn’t solve the problem. Could it be that the path to this specific file is too long?

I’d appreciate some help to get this resolved, cheers!

The page I need help with: [log in to see the link]