I'm running CE v 18.104.22.168 and have come across an issue where only UPS and a Free Shipping setup will appear. My USPS credentials are valid. The USPS functions all worked in ce v1.8, which is the only other version I have used.
My experience with Magento is less than a year and I'm not sure where to look to find why this is going on. There is nothing in the error logs.
And, yes, I do have USPS enabled in Shipping Methods.
I searched the forums and saw a couple similar questions, but nothing that contained a working solution. I'm hoping by bumping the question perhaps someone who has solved the dilemma can provide some pointers.