Facebook ads – potential reach suddenly drops – cost shoots up

Hi All, I am facing this multiple times now in running facebook ads. All of a sudden the potential reach of an ad set dropped by 1/100th. (in the audience definition at the top right where fb shows if it is too specific or broad)

In the latest instance, when I created/started a campaign, the target reach was around 200,000. However after 2 days, the target reach is now showing around 2000. The lead cost also is very high. I am facing this second or third time now. The previous instances were for landing page conversion and the impressions would not increase and the ad utilized the budget very slowly - which i guess is due to the very small audience.

But in this case the ad just ate up the budget but no result.

Has anyone faced this?

I face other serious issues with fb ads, which I will make a separate post.