I think that @Joel_Jantsen is right, the ad is probably shadowbanned because base on your description that you've got no flags that would indicate of a violation or that you were doing something wrong or changing any of the settings, that's the most likely thing that would happen to that ad. No errors but the ads aren't resulting in any traffic, that's the only thing that I can think of, I hope that you get that business ad up and running again, it's a small business after all and I feel bad for the possibility that you were shadowbanned. Is there a possibility that you've missed something in their terms in conditions regarding ads?
I highly doubt I have missed anything.
This can't be something related to the terms of service. Not when it comes to the page publications and posts anyway because if that was the case, no one would've been able to boost them or create ads but that's not the case here. Only I cannot do that. As I have said, I thought its my card at first, but I eliminated that possibility after trying another one.
I have also tried to "Boost again" by clicking some of the ads I ran in the past without any issues, just in case I have missed certain settings, but those do not run either.