First of all, give info about hardware and software versions.

What switches do you connect, managed or unmanaged? Maybe, it has some kind of IP-conflict?

Jek wrote

Hi, I have TP LINK TL-R470T+ with pldt and globe isp in port 1 and port 2. When I connect switch to port lan port 5 computers have internet connection but when I connect another switch to port 3 or 4 internet connection is not working to both switches but when I connect my laptop to port 3 or 4 internet connection is working in my laptop as well in switch connected to port 5. What should I do. please help me. Thank you.

Hi Jek

If you use the managed switch, you should pay attention to the IP address of TL-R470T+ and your switch. TL-R470T+ uses 192.168.0.1 as default IP, if the switch uses the same IP, they will have the IP address conflict as Mitya said.

Hi, thank you for noticing. I really appreciated it. I used 2 cisco switch which having a problem with the connection. Those are unmanaged switch. Do I need to configure port 3 and 4 on my load balancer? 

Thank you.

Hi. Thank you for noticing. I used 2 cisco switch CISCO SG100D. Those are unmanaged. Is there something to do to the load balancer or I need to configure port 3 and 4 in my load balancer? Thank you.

If everything works when you connect directly to port 3/4/5, then it must work when you connect it via unmanaged switch. It is kinda weird in fact. 

Load Balancing is configured only for WAN ports, like if you have 2 cables from your ISP (WAN1, WAN2), then you can configure it to work together or as Link Backup, but it doesn't affect you LAN network. Check, that your ports 3,4,5 are LAN, not WAN. Check, that you do not have a loop, when you connect your switches between each other or some PC to be connected to both switches. I still guess, it is some sort of physical or logical problem, not a problem of 470T+ configuration.

Jek wrote

Hi. Thank you for noticing. I used 2 cisco switch CISCO SG100D. Those are unmanaged. Is there something to do to the load balancer or I need to configure port 3 and 4 in my load balancer? Thank you.

Please check if the port LED lights up. R470T+ is 100Mbps router, please make sure that your switch support 100Mbps as well.