Select2 error in console: TypeError: Cannont read property 'select2' of undefined

[iamalex2]

Can someone help with this error. I can't find anything wrong:
TypeError: Cannot read property 'each' of undefined
at $.fn.select2 (vendor.js:91685)
at Object.Ember.assert (vendor.js:14406)
at frontend.js:2255
at tryCatch (vendor.js:60913)
at invokeCallback (vendor.js:60925)
at publish (vendor.js:60896)
at vendor.js:39035
at Queue.invoke (vendor.js:11326)
at Object.Queue.flush (vendor.js:11391)
at Object.DeferredActionQueues.flush (vendor.js:11196)RSVP.onerrorDefault

{{select-2
placeholder=ph.location
value=locationsProxy
typeaheadSearchingText="Search location"
typeaheadNoMatchesText="No locations found for '%@'"
query="queryLocations"
multiple=true
}}