Screen grays out and needs to be refreshed when clicking Select Delegates in an Event

Trying to populate Delegates with a Target List for an event, but as soon as I click Select Delegates, the screen grays out and I can’t do anything except refresh. Currently can’t attach the screenshot, but the options for Targets/Target lists pops up in the middle of the screen then it grays out and dies.

We are using version 7.8.17

I just tested this on a 7.8.19 and it works fine.

Maybe you can look for clues in your logs or in your browser’s Developer Console.

If it’s a big Target List, I would try it with a very small one just to see if it works. If it does, look for resources related issues, namely php.ini settings for memory or timeouts. These will leave a message in the logs anyway.