[Plugin: G-Lock Double Opt-in Manager] Subscribe button is cut

For some reason the subscribe button is not complete on certain browsers and only shows part of the word “subscribe”. On other browsers there is no problem.

Any idea how to fix this?

https://www.freeprintables4kids.com/receive-updates-on-free-printables/

https://www.ads-software.com/extend/plugins/g-lock-double-opt-in-manager/