Glad it’s sorted out. (I much prefer to say “storage” when I mean disk space, and “memory” when I mean RAM.) In this case, your problem was a lack of storage space - and indeed, a 25G instance is quite small, but still practical for a small forum. It’s always true that upgrading (updating, rebuilding) demands more resources than just running the forum.
As a tip for anyone in future, see perhaps here:
Or here: