I am unable to write to my USB drive connected to my Tp-link router. 

I looked for a solution on the TP-Link community and found the following:

https://community.tp-link.com/us/home/forum/topic/221706

I added the windows credential as per the stated solution. It worked once and I was able to add a new file to my USb drive. But then it did not work after that on my windows computer.

Any help is greatly appreciated.