How to get encryption working on Oneplus 3T



I have installed /e/ onto a OnePlus 3T. I would like to encrypt the phone. I go to the settings page and select encrypt phone, then work through all the dialogues then when I start the encryption, it brings up the full screen android image, then reboots without doing any encryption. I have setup a PIN before trying this. Any ideas what steps I must take to make this work?

Thank you!