I just found out what causes this problem. It always occurs when your browser language is other than English. To fix this, you have to go to your browser settings and change your default language to "English (US)". After I did that, the error no longer occurs. Some other problems I had with USPS site also got cleared once I did that.
I just found out what causes this problem. It always occurs when your browser language is other than English. To fix this, you have to go to your browser settings and change your default language to "English (US)". After I did that, the error no longer occurs. Some other problems I had with USPS site also got cleared once I did that.