Problem: The issue here is that the user is getting an error 500 when trying to save his user fields.
Solution: Normally when we get error 500 we usually encourage our customers to enable the wordpress debugging, this way we can get an understanding of the error at hand.
To enable it please follow the instructions in the link below. https://www.a2hosting.com/kb/installable-applications/optimization-and-configuration/wordpress2/debugging-wordpress
Sometimes the error will help you to resolve the issue.
This is the technical support forum for Toolset - a suite of plugins for developing WordPress sites without writing PHP.
Everyone can read this forum, but only Toolset clients can post in it. Toolset support works 6 days per week, 19 hours per day.