Unable to connect to internet via router (Tp link 740n)

The router worked fine in the past until recently, my ISP had a break in the cable line and repaired it.
Now, I am unable to connect to the internet.
If I connect the ISP's LAN cable directly to PC (windows 7) and do the following steps:
  1. Control panel > View network stats and tasks
  2. Setup a new connection or network > Connect to the internet > Next
  3. Broadband PPPOE > Next
  4. Type in username, password > Connect

Internet works fine. This means there is no problem with the internet connection.
However, if I connect the ISP's LAN cable to the "blue" port of the router

and the short LAN cable to my PC then do the following steps:

  1. Open http://tplinklogin.net/ (It shows me router config page)
  2. Click Quick setup > Next
  3. Select PPPoE > Next
  4. Type in username, password > Next
  5. Leave the Wireless Page untouched > Next
  6. Click Reboot (Wait till router reboots)
It does not work, the router page shows "Connecting..." but does not connect at all.
Here's the router log:

####################################################################
# TL-WR740N System Log
# Time = 1970-01-01 0:10:08 609s
# H-Ver = WR740N v4 00000000 : S-Ver = 3.16.6 Build 130529 Rel.47286n
# L = 192.168.0.1 : M = 255.255.255.0
# W1 = PPPoE : W = 0.0.0.0 : M = 0.0.0.0 : G = 0.0.0.0
####################################################################

1st day 00:07:02 OTHER INFO User clear system log.
1st day 00:07:17 PPP NOTICE PPPoE start connecting...
1st day 00:07:19 PPP NOTICE Standard authentication.
1st day 00:07:19 PPP INFO pppd start
1st day 00:07:19 PPP INFO sent [PADI Host-Uniq(0x00000297)]
1st day 00:07:24 PPP INFO sent [PADI Host-Uniq(0x00000297)]
1st day 00:07:34 PPP INFO sent [PADI Host-Uniq(0x00000297)]
1st day 00:07:54 PPP ERROR Timeout waiting for PADO packets
1st day 00:08:04 PPP NOTICE Standard authentication.
1st day 00:08:04 PPP INFO pppd start
1st day 00:08:04 PPP INFO sent [PADI Host-Uniq(0x000002de)]
1st day 00:08:09 PPP INFO sent [PADI Host-Uniq(0x000002de)]
1st day 00:08:19 PPP INFO sent [PADI Host-Uniq(0x000002de)]
1st day 00:08:39 PPP ERROR Timeout waiting for PADO packets
1st day 00:08:51 PPP NOTICE Standard authentication.
1st day 00:08:51 PPP INFO pppd start
1st day 00:08:51 PPP INFO sent [PADI Host-Uniq(0x0000030d)]
1st day 00:08:56 PPP INFO sent [PADI Host-Uniq(0x0000030d)]
1st day 00:09:06 PPP INFO sent [PADI Host-Uniq(0x0000030d)]
1st day 00:09:26 PPP ERROR Timeout waiting for PADO packets
1st day 00:09:38 PPP NOTICE Standard authentication.
1st day 00:09:38 PPP INFO pppd start
1st day 00:09:38 PPP INFO sent [PADI Host-Uniq(0x00000344)]
1st day 00:09:43 PPP INFO sent [PADI Host-Uniq(0x00000344)]
1st day 00:09:53 PPP INFO sent [PADI Host-Uniq(0x00000344)]