double negative sentence

Hello teachers!

There is a fairly confusing double negative sentence that don't know whether I should see two negative indicators(unlikely & unable) as positive or take it as double emphasis for being negative?

Here's the sentence:

I am afraid it is unlikely that we will be unable to accept any further registrations.

I know that if the sentence goes 'it is likely that we will be unable.. ' or 'it is unlikely that we will be able..' carry the same meaning of refusing politely, but what about in this context, does it mean 'able' or 'unable' ?

And does the word 'any' here contain a negative sense at all?

To avoid such confusion to English learners like me , what would you suggest to distinguish the meaning of double negative sentences?

Thank you!