Strange Wifi Throttling / Slowdown every month

[d4n1Xd34th]

Hello People, I am facing a strange problem with my router. It's a D-Link DIR-600M

Every few days in the beginning of the month, I face a strange slowdown issue. Pages take time to load or redirect and chrome status keeps spinning a long time before loading / redirecting. 

Also my phone keeps disconnecting from the network, and does not connect unless i switch off my phone's wifi off and on again

 

First I thought it's the ISP throttling the data, but it's not.

If i use a Ethernet cable from the router to my laptop, the speed issue does not exist.

It takes time even to load 192.168.0.1 even though its a local page.

 

Any idea what might cause this issue?

 

I have checked the active client table for pirates, but there are none.

The problem occurs over multiple devices including mobile phones and other laptops.

 

[Mad153]

what's your link speed when this happens?

https://www.windowscentral.com/how-determine-wi-fi-and-ethernet-connection-speed-windows-10#:~:text=Click on Status.,View your network properties option.&text=Under the "Properties" section%2C,(Receive%2FTransmit) field.