I have been trying to crate a new payment on my Santander account. The process stalls with Ice dragon, but works OK with Microsoft Edge Version 89.0.774.68 and Firefox 87.0.
Does the site give a reason why that is happening?
With the development of IceDragon lagging seriously behind to Firefox browser, on which it is based, I suggest to access your bank with recent versions of other browsers. We may be looking at a website compatibility issue in which age of the browser plays a role.