Hi Guys,
I had this same issue with the latest build of Ultimate Member (2.0.23) and latest build of wordpress
first went through the article on their support page https://docs.ultimatemember.com/article/114-photo-uploads-not-working
without any joy.
I then found this forum and did my own version of the conflict test as the site was already live and I couldn’t justify changing the theme, etc.
I simply went through each plugin one at a time disabling and retesting until I got the Profile Photo Upload working again.
Long story short my problematic plugin was ‘Fast Velocity Minify‘
Disabled that plugin and retested and photo uploaded without any problem at all.
Hopefully this will help someone a little quicker.
