Due to too many invalid headers, have no block source #8027

I'm on Ubuntu 14.10 using this version Bitcoin Core version v0.12.0.0-g188ca9c (64-bit)

But have no block source available and the log is full of those entries

...
2016-05-09 06:26:09 ProcessMessages(headers, 162003 bytes) FAILED peer=11
2016-05-09 06:26:15 connect() to 198.27.82.55:8333 failed after select(): Connection refused (111)
2016-05-09 06:26:43 connect() to 78.42.181.117:8333 failed after select(): No route to host (113)
2016-05-09 06:27:00 connect() to 23.92.53.139:8333 failed after select(): Connection refused (111)
2016-05-09 06:27:18 connect() to 89.173.121.14:8333 failed after select(): Connection refused (111)
2016-05-09 06:28:00 ERROR: AcceptBlockHeader: prev block invalid
2016-05-09 06:28:00 Misbehaving: 54.232.245.146:8333 (0 -> 100) BAN THRESHOLD EXCEEDED
2016-05-09 06:28:00 ERROR: invalid header received
2016-05-09 06:28:00 ProcessMessages(headers, 162003 bytes) FAILED peer=8

Googled everywhere and didn't find a solution. Hope someone of you can tell me what I could do?

Thanks heaps

Also earlier at the beginning I see interesting log entries:

2016-05-09 06:11:53 Bitcoin version v0.12.0.0-g188ca9c (Wed, 17 Feb 2016 09:40:03 +0100)
2016-05-09 06:11:53 InitParameterInteraction: parameter interaction: -whitelistforcerelay=1 -> setting -whitelistrelay=1
2016-05-09 06:11:53 Using OpenSSL version OpenSSL 1.0.2d 9 Jul 2015
2016-05-09 06:11:53 Using BerkeleyDB version Berkeley DB 4.8.30: (April  9, 2010)
...
2016-05-09 06:12:09 init message: Verifying blocks...
2016-05-09 06:12:09 Verifying last 288 blocks at level 3
2016-05-09 06:14:17 No coin database inconsistencies in last 8 blocks (5915 transactions)
2016-05-09 06:14:17  block index          138424ms
2016-05-09 06:14:17 CTxMemPool::ReadFeeEstimates(): unable to read policy estimator data (non-fatal)
2016-05-09 06:14:17 init message: Loading wallet...
2016-05-09 06:14:17 nFileVersion = 120000
2016-05-09 06:14:17 Keys: 0 plaintext, 204 encrypted, 2 w/ metadata, 204 total
2016-05-09 06:14:17  wallet                   56ms
2016-05-09 06:14:17 init message: Activating best chain...
2016-05-09 06:14:17 mapBlockIndex.size() = 343665
2016-05-09 06:14:17 nBestHeight = 330428
2016-05-09 06:14:17 setKeyPool.size() = 100
2016-05-09 06:14:17 mapWallet.size() = 4
2016-05-09 06:14:17 mapAddressBook.size() = 2
2016-05-09 06:14:17 init message: Loading addresses...
2016-05-09 06:14:17 torcontrol thread start
2016-05-09 06:14:17 Loaded 15162 addresses from peers.dat  83ms
2016-05-09 06:14:17 init message: Done loading
2016-05-09 06:14:17 msghand thread start
2016-05-09 06:14:17 net thread start
2016-05-09 06:14:17 addcon thread start
2016-05-09 06:14:17 opencon thread start
2016-05-09 06:14:17 dnsseed thread start
2016-05-09 06:14:17 AddToWallet 6d4494379cad9e4675388416199a5e5e5f957be4ca80acc76a4958c3c32153df  
2016-05-09 06:14:17 GUI: Platform customization: "other" 
2016-05-09 06:14:17 GUI: PaymentServer::LoadRootCAs: Loaded  174  root certificates 
2016-05-09 06:14:18 connect() to 81.180.208.99:8333 failed after select(): No route to host (113)
2016-05-09 06:14:28 Loading addresses from DNS seeds (could take a while)
2016-05-09 06:14:33 193 addresses found from DNS seeds
2016-05-09 06:14:33 dnsseed thread exit
2016-05-09 06:15:10 connect() to 60.29.215.241:8333 failed after select(): Connection refused (111)
2016-05-09 06:16:03 connect() to 162.219.176.178:8333 failed after select(): No route to host (113)
2016-05-09 06:16:20 connect() to 192.227.141.13:8333 failed after select(): Connection refused (111)
2016-05-09 06:16:21 connect() to 119.81.164.42:8333 failed after select(): Connection refused (111)
2016-05-09 06:16:25 connect() to 162.219.179.82:8333 failed after select(): No route to host (113)
2016-05-09 06:16:53 receive version message: /Satoshi:0.12.1/: version 70012, blocks=410948, us=58.28.152.233:59062, peer=1
2016-05-09 06:16:54 ERROR: AcceptBlockHeader: block is marked invalid
2016-05-09 06:16:54 ERROR: invalid header received
2016-05-09 06:16:54 ProcessMessages(headers, 162003 bytes) FAILED peer=1
2016-05-09 06:16:59 connect() to [2a01:4f8:171:2f28::2]:8333 failed: Network is unreachable (101)
2016-05-09 06:17:27 connect() to 49.159.186.178:8333 failed after select(): Connection refused (111)
2016-05-09 06:17:28 connect() to 208.163.247.106:8333 failed after select(): Connection refused (111)
2016-05-09 06:17:29 connect() to 92.106.212.142:8333 failed after select(): Connection refused (111)
...

Looks like hardware failure.

You should reindex.

ok, will do. but would be good if i see such a warning that re-indexing is needed. somewhere on the UI.