TP-LINK tl-mr6400 does not give internet access to connected devices
Hi I am using a new router tl-mr6400 with a Sim card from Movistar in Colombia. When I first received the router, I set it up following the manual and it worked properly for a few days, but now it is not working. I go and check the configuration and everything seems to be ok, the network map and the other network/internet options in the menu show that there is internet in the device, but when I connect my computer or any other device like my phone to that network I cannot have internet access, I cannot load any webpage. I know for sure the sim card has internet access because when I hired the sim card services it came with another router from that company, which is smaller in capacity compared with this to link router, and when I test the sim card in that other device everything works fine and I can have access in my computer and phone.
I would like to know if there is anything I am not checking well or missing so I can use again my new router, which by the way before it stopped working, was working very well.