Added new fields -> form not saving to database

Hi

Chronoforms V5 => Joomla 3.9.1 => PHP 7.2.13 => MySql 5.5.5

Have a working form that is connected to the Joomla Users table. Added two new fields . Did this in PhpMyAdmin.
Added the fields to the form but not saving. Compared closely to other form fields that are saving properly, seems set up correctly.
Any clues where I should start looking?
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Thanks

Well you shouldn't add fields to core tables for a start. Use Joomla's custom fields and add your data to the #__fields_values table.

Found Answer
Need to press the Delete Cache icon in the Forms Manager toolbar to update the file structure - applies to V5

Oh, thanks Healyhatman
What is the risk if I add fields to the Users table?

That you could lose them when updating Joomla or repair your core tables after an error

That's serious.
I'll read up on how to combine the core Users with custom fields, thanks