If you use eSIMs extensively you may have wondered how many eSIM services can be installed in the eSIM chip in the iPhone. The eSIM chip in the iPhone can hold up to 20 different eSIM services.
Once this number are installed you will get a ‘locked phone’ error message – see http://www.esim.net/helpdesk/knowledge-base/iphone-download-error-messages/
You will have to delete one of the services before you can install another one.