Learn English – the correct meaning of “held up” here

Neither. "This makes no sense" means that the speaker cannot construct a rational argument as to why the particular situation (whatever "this" is) should be true or reasonable, and in particular contends that it is false or unreasonable.

"We'll go tomorrow."

"That makes no sense; the shop is closed tomorrow!"

ETA: this is quite a strong statement, so you had better be able to back it up if you don't want to cause offense!

I think it's worth mentioning some of the complexities involved, though many of these were mentioned at the thread Andrew links to.

Choice of tense probably isn't as clear-cut as we'd like to think. For instance, with disease-related examples as mentioned in the link:

I have diabetes /a cold / occasional headaches / frequent headaches.

*I am having diabetes / a cold.

I am having occasional headaches / frequent headaches.

The use of have as a near-synonym of get / take (punctual) as well as possess / suffer from (durative) is doubtless a complicating factor here.

Turning to the multi-word verb get on, we see that again there is idiosyncratic behaviour dependent upon the particular 'object referent' (whether stated overtly or not):

I hear you've got a new job. How are you getting on? [ie with your new job]

I was sorry to hear that you and Bill had a big argument (last month). How are you getting on with him now?

I was sorry to hear that you and Bill had a big argument. How are you getting on now?

and for the do + bare infinitive:

*I hear you've got a new job. How do you get on?

Travelling by bus must be hard for you now. How do you get on? [different sense of get on, of course]

*I was sorry to hear that you and Bill had a big argument last week. How do you get on (with him) now?

I was sorry to hear that you and Bill had a big argument last year. How do you get on (with him) now?

There seem to be subtleties involving not only the continuous / repetitive distinction, but also whether the present state can be regarded as steady (involving how long it has continued).