.nic, .gov sites and X app seems to work fine on Jio at my end. The below images are sent using Jio only. But yes, Imgur has some API issues recently and it is not specific to Jio. It fails sometimes.
Maybe you can try a different browser. Or use a VPN for time being. Sometimes disabling the VPN, if you already using one, will fix issues related to govt sites. It is more likely an IP related issues. It has to be addressed by Jio only.