https issue - map not loading because of mixed content

[tomhermans]

related: I, or rather my client, has an issue with https. Map etc is not displayed, because of mixed content issues: https://www.theuma.com/nl-nl/over-theuma/verkooppunten/

Is there a fix for this ?

Console:

Mixed Content: The page at 'https://www.theuma.com/nl-nl/over-theuma/verkooppunten/' was loaded over HTTPS, but requested an insecure script 'http://www.theuma.com/theumawp2018/?simplemap-master-js=1&smpid=746&ver=4.9.8'. This request has been blocked; the content must be served over HTTPS.
jquery.min.js?ver=3.2.1:2 jQuery.Deferred exception: load_simplemap is not defined ReferenceError: load_simplemap is not defined
at HTMLDocument. (https://www.theuma.com/nl-nl/over-theuma/verkooppunten/:401:5)
at j (https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js?ver=3.2.1:2:29999)
at k (https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js?ver=3.2.1:2:30313) undefined
r.Deferred.exceptionHook @ jquery.min.js?ver=3.2.1:2
jquery.min.js?ver=3.2.1:2 Uncaught ReferenceError: load_simplemap is not defined
at HTMLDocument. ((index):401)
at j (jquery.min.js?ver=3.2.1:2)
at k (jquery.min.js?ver=3.2.1:2)
/theumawp2018/theumawp2018/wp-content/uploads/2018/04/regts_120x50.jpg:1 Failed to load resource: the server responded with a status of 404 ()