Strange issue with Reliance Wimax

I have connected the reliance wimax modem output to my Linksys router and it works quite well for last 1 year.
I have static IP address. Recently my antenna was not working and they replaced the same.

Now whenever the modem power goes down, I have to unplug cable from the router, connect to desktop and once the connection establishes, I have to put it back to the router.
Its very rare that it gets reconnected automatically with the network connected to the router directly. Once connected, I don't have issue.

Does anybody know what could be the issue ?.

I have tried all the version of firmware with the router and doesn't help.

Tried connecting to Telsima starmax 2150 antenna router and see any settings there but nothing helped.

anybody knows what could be the issue ?.

I used to have Reliance wimax a couple of years ago and had the same problem. Your best bet to have an always on internet connection is to keep your modem on at all times. My connection used to take upto 20 mins to get an IP after switching on.