It is valid. Due to the influx in transaction volume, the mempool size for Blockchain.info has presumably increased. As a result, the minimum fees for it to be entered into their mempool/block explorer has increased. They evicted your transaction from your mempool which isn't of any concern but it's wrong to display it as invalid.

If you do an RBF with sufficient fees, it will definitely be confirmed within a reasonable period of time. 1 satoshi/vbyte probably won't make the cut for a long time.