Can’t upload photo

I just installed the latest version of Ultimate Member (2.1.4) and can’t upload either a profile photo or a cover photo. The JS console reports the following:

Uncaught TypeError: e.indexOf is not a function
    at k.fn.init.k.fn.load (jquery-3.4.1.min.js?ver=3.4.1:2)
    at Object.<anonymous> (um-functions.min.js?ver=2.1.4:1)
    at Function.each (jquery-3.4.1.min.js?ver=3.4.1:2)
    at Object.onSuccess (um-functions.min.js?ver=2.1.4:1)
    at Object.success (um-fileupload.min.js?ver=2.1.4:1)
    at Object.E.success (um-jquery-form.min.js?ver=2.1.4:1)
    at c (jquery-3.4.1.min.js?ver=3.4.1:2)
    at Object.fireWith [as resolveWith] (jquery-3.4.1.min.js?ver=3.4.1:2)
    at l (jquery-3.4.1.min.js?ver=3.4.1:2)
    at XMLHttpRequest.<anonymous> (jquery-3.4.1.min.js?ver=3.4.1:2)
k.fn.load @ jquery-3.4.1.min.js?ver=3.4.1:2
(anonymous) @ um-functions.min.js?ver=2.1.4:1
each @ jquery-3.4.1.min.js?ver=3.4.1:2
onSuccess @ um-functions.min.js?ver=2.1.4:1
success @ um-fileupload.min.js?ver=2.1.4:1
E.success @ um-jquery-form.min.js?ver=2.1.4:1
c @ jquery-3.4.1.min.js?ver=3.4.1:2
fireWith @ jquery-3.4.1.min.js?ver=3.4.1:2
l @ jquery-3.4.1.min.js?ver=3.4.1:2
(anonymous) @ jquery-3.4.1.min.js?ver=3.4.1:2
load (async)
send @ jquery-3.4.1.min.js?ver=3.4.1:2
ajax @ jquery-3.4.1.min.js?ver=3.4.1:2
(anonymous) @ um-jquery-form.min.js?ver=2.1.4:1
X.fn.ajaxSubmit @ um-jquery-form.min.js?ver=2.1.4:1
w @ um-fileupload.min.js?ver=2.1.4:1
m @ um-fileupload.min.js?ver=2.1.4:1
(anonymous) @ um-fileupload.min.js?ver=2.1.4:1
dispatch @ jquery-3.4.1.min.js?ver=3.4.1:2
v.handle @ jquery-3.4.1.min.js?ver=3.4.1:2

There do not appear to be any PHP errors.

Is there anything I can do to get around this?