Unable to save email settings

I've been following the following documentation: https://world.mendix.com/display/public/howto6/Send+Custom+Emails+From+Your+App I'm currently at step 3 'Configuring SMTP Settings'. When I go to settings, I see a page where I have to enter my SMTP settings which I filled in as following: After having it filled like above, I clicked the "Save" button, but I got the following error: However when I try to test it by clicking the "Test" button it works and an email gets sendt. The errors I get in the console after having clicked the "Save" button: How can I get the save button to work?
1 answers

There is a constant in the Encryption module called "EncryptionKey". You need to specify a 16-character value for it that constant.