it’s not what expected, usually just a hole in the glass.
It looks like bulkhead in the glass hole with a seal (so could leak from that) then the standpipe (which needs a gasket as well) is held in place with the nut. Is that what you see?
If any of that is true, which one is leaking, from stand pipe onto that second contraption then out through the glass or just that second contraption.
I’d replace the seal on the stand pipe, put it back in and tighten nut and see if it still leaks.
If it does, it’s not the standpipe.
It looks like bulkhead in the glass hole with a seal (so could leak from that) then the standpipe (which needs a gasket as well) is held in place with the nut. Is that what you see?
If any of that is true, which one is leaking, from stand pipe onto that second contraption then out through the glass or just that second contraption.
I’d replace the seal on the stand pipe, put it back in and tighten nut and see if it still leaks.
If it does, it’s not the standpipe.