That might have something to do with it.

Simple:Press 5.5.3 is needed to work properly with WordPress 4.1. When 5.5.1 was released W was still using the wp-config.php setting exclusively and things are a lot different.

I would expect there to be quite a few other small issues as well.

Upgrading to 5.5.3 from 5.5.1 resolved the translation issue. Thank you.

good to hear… thanks for the update..