I have the same problem.
Whenever I open the BLTP it just keeps loading and loading no matter what I do.
All I see is a yellow circle spinning for roughly 1 or 2 minutes and a completely blank BLTP screen afterwards. I don’t even have a search bar available to me or anything.
The only thing I can do is collect stuff I bought earlier.
This has started happening to me the evening before the first halloween update.
Before that, everything was fine. Neither of the steps in the OP helped me at all.