@Hawaii-5-0 My model is, Router Model: TP-Link ARCHER-C7 v4 . I think we can download the TP-Link firmware form their website if we need to re-install it.

Well, I installed this 3rd party firmware DD-WRT v3.0 - r40559 std (08/06/19) and it fixed the issue.

@SirDigital I'm using Archer C7 router and I have attached a seagate 8TB drive with separate power supply for backup purposes. I was copying lot of files to the drive from another drive and today a...