Hello @Shamir.from.Calgary.Alberta ,
Does recreating the tweet and trying to post the new one work, or reducing the number of characters - even if you're already within the limit? Beyond that, it may be that there's too much traffic coming into Twitter resulting in certain 3rd party API restrictions, and it'll just be a matter of trying to post at a later time.
When I try and re-post it manually, it goes through. I'd say this is a bug that needs addressed. The way I use the social post is to announce my live webinar with a 30 minute lead time. If the tweet fails, then there is little value in me manually sending it through. The facebook post goes right through without effort.