3514876 - Error "Cannot create extension field in this UI; Extension Field limit reached; An exception was raised" Occurs While Creating Extension Field.

You are adding an extension field and you receive an error "Cannot create extension field in this UI; Extension Field limit reached; An exception was raised."
 
Also, If you try to modify the existing fields (like adding new values on list fields) you may receive the following message: "Modification of the field properties failed; There has been an exception".

SAP Cloud for Customer HTML5 and RUI UI

Field, Form, SDK, Limit of fields, extension, field, limit, aggregate, length. , KBA , AP-RC-UIF-FLX , Page Layout & Key User Configuration , Problem