Swap USDC into PAID on UNI and my USDC disappeared

Hi there,
I wanted to swap an amount of USDC into PAID NETWORK on UNI, and I did as I used to do. I had to confirm first both on UNI and on my Metamask wallet, had ETH and did it.
Then suddenly instead of seeing the swap button to finalize my SWAP, a grey rectangle appeared upon UNI saying Insufficient amount and whenI checked both my USDC and PAID tokens (actually not yet possible), nothing showed up, the USDC disappeared, zero.
Besides, the were enough ETH for the gas fees.