The search engine only works once

If I have Advanced Search enabled it works well, if I disable Advanced Search then I see the same thing you do.

The problem happens to me both with Advanced Search enabled or disabled

With advanced search enabled, the search button is reenabled if I enter a new search string or if I click on advanced search and clear the search filters then the search button is reenabled.

I am inserting the search form using a shortcode, I don’t know if that has anything to do with it

What shortcode did you use to insert the search form? I used the following shortcode and it worked:

[events_calendar  has_search=1 show_search=1 views="calendar,grid,list,map" scope="future"]

I checked it again and with Advanced Search it works, but not with the basic search
A simple one:

[event_search_form]

I’m having the same issue.
I do a first search and it works fine. Then if I delete my search parameters and try to do a new one, the search button is disabled and I can’t execute the search.
The only way to re-enable the search button is to go in advanced search parameters, and change a setting in there.

Thing I noticed is that it works again only if the Country option is activated in the advanced search parameters.
Once I disable this option, then the search engine is back to working only once, setting the search button in disabled mode.