As the least techno-savvy old lady on the planet, (I'm on a laptop called a Chromebook, whatever that is) I've found I can access Mudcat by using the 'remove all browsing data' via 'more tools', then starting up my laptop again from scratch, and Mudcat comes up very quickly. If I don't do this, it won't load at all.
Can't believe I'm even offering this advice, as I'm about at the level of an amoeba where computers and the Internet are concerned :)