I don't know, how about to sync altcoin with my computer.

I see debug.log file of my wallet. Does it show peers? In addition, look at the debug.log file, it might show specific problem information. Here image :
2017-05-18 01:37:23 BITICOIN version v1.0.0.0-g9cffb23-beta (Mon, 12 Jan 2015 16:55:18 -1000)
2017-05-18 01:37:23 Using OpenSSL version OpenSSL 1.0.2f 28 Jan 2016
2017-05-18 01:37:23 Default data directory C:\Users\MyPC\AppData\Roaming\BITICOIN
2017-05-18 01:37:23 Using data directory C:\Users\MyPC\AppData\Roaming\BITICOIN
2017-05-18 01:37:23 Using at most 125 connections (2048 file descriptors available)
2017-05-18 01:37:23 Using 2 threads for script verification
2017-05-18 01:37:23 init message: Verifying wallet...
2017-05-18 01:37:23 dbenv.open LogDir=C:\Users\MyPC\AppData\Roaming\BITICOIN\database ErrorFile=C:\Users\MyPC\AppData\Roaming\BITICOIN\db.log
2017-05-18 01:37:23 Bound to [::]:17935
2017-05-18 01:37:23 Bound to 0.0.0.0:17935
2017-05-18 01:37:23 init message: Loading block index...
2017-05-18 01:37:23 Opening LevelDB in C:\Users\MyPC\AppData\Roaming\BITICOIN\blocks\index
2017-05-18 01:37:23 Opened LevelDB successfully
2017-05-18 01:37:23 Opening LevelDB in C:\Users\MyPC\AppData\Roaming\BITICOIN\chainstate
2017-05-18 01:37:23 Opened LevelDB successfully
2017-05-18 01:37:23 LoadBlockIndexDB(): last block file = 0
2017-05-18 01:37:23 LoadBlockIndexDB(): transaction index disabled
2017-05-18 01:37:23 Initializing databases...
2017-05-18 01:37:23 2c436e243299de303ae0151701be214bf49c0e6672a36618d8624553c6a29abb
2017-05-18 01:37:23 2c436e243299de303ae0151701be214bf49c0e6672a36618d8624553c6a29abb
2017-05-18 01:37:23 bad286ebbfeab401518a2f91b39a4a753f351c98d04001d66a3bbf45a8eb618e
2017-05-18 01:37:23 CBlock(hash=2c436e243299de303ae0151701be214bf49c0e6672a36618d8624553c6a29abb, input=0100000000000000000000000000000000000000000000000000000000000000000000008e61eba845bf3b6ad60140d0981c353f754a9ab3912f8a5101b4eabfeb86d2bac4531a59f0ff0f1e7e3c0900, PoW=000006a3675681ff622668c17be290dead07aa3c12cf1f5718ae955ffd20d44e, ver=1, hashPrevBlock=0000000000000000000000000000000000000000000000000000000000000000, hashMerkleRoot=bad286ebbfeab401518a2f91b39a4a753f351c98d04001d66a3bbf45a8eb618e, nTime=1494897604, nBits=1e0ffff0, nNonce=605310, vtx=1)
2017-05-18 01:37:23 CTransaction(hash=bad286ebbfeab401518a2f91b39a4a753f351c98d04001d66a3bbf45a8eb618e, ver=1, vin.size=1, vout.size=1, nLockTime=0)
CTxIn(COutPoint(0000000000000000000000000000000000000000000000000000000000000000, 4294967295), coinbase 04ffff001d010424692077696c6c20746f206272696e67206d7920636f696e20676f20746f20776 f726c642e)
CTxOut(nValue=2500.00000000, scriptPubKey=04405ee24e824e5568d6546dfd83c2)
vMerkleTree: bad286ebbfeab401518a2f91b39a4a753f351c98d04001d66a3bbf45a8eb618e
2017-05-18 01:37:23 Pre-allocating up to position 0x1000000 in blk00000.dat
2017-05-18 01:37:23 SetBestChain: new best=2c436e243299de303ae0151701be214bf49c0e6672a36618d8624553c6a29abb height=0 log2_work=20.000022 tx=1 date=2017-05-16 01:20:04 progress=1.000000
2017-05-18 01:37:23 init message: Verifying blocks...
2017-05-18 01:37:23 block index 32ms
2017-05-18 01:37:23 init message: Loading wallet...
2017-05-18 01:37:23 nFileVersion = 1000000
2017-05-18 01:37:23 wallet 234ms
2017-05-18 01:37:23 init message: Loading addresses...
2017-05-18 01:37:23 ERROR: CAddrman::Read() : open failed
2017-05-18 01:37:23 Invalid or missing peers.dat; recreating
2017-05-18 01:37:23 Loaded 0 addresses from peers.dat 0ms
2017-05-18 01:37:23 mapBlockIndex.size() = 1
2017-05-18 01:37:23 nBestHeight = 0
2017-05-18 01:37:23 setKeyPool.size() = 100
2017-05-18 01:37:23 mapWallet.size() = 0
2017-05-18 01:37:23 mapAddressBook.size() = 1
2017-05-18 01:37:23 AddLocal([2001:0:9d38:90d7:28d2:16e:8b98:b88f]:17935,1)
2017-05-18 01:37:23 dnsseed thread start
2017-05-18 01:37:23 upnp thread start
2017-05-18 01:37:23 Loading addresses from DNS seeds (could take a while)
2017-05-18 01:37:23 1 addresses found from DNS seeds
2017-05-18 01:37:23 dnsseed thread exit
2017-05-18 01:37:23 net thread start
2017-05-18 01:37:23 addcon thread start
2017-05-18 01:37:23 opencon thread start
2017-05-18 01:37:23 msghand thread start
2017-05-18 01:37:23 trying connection 192.168.0.104:17935 lastseen=387519.8hrs
2017-05-18 01:37:23 dumpaddr thread start
2017-05-18 01:37:23 connected 192.168.0.104:17935
2017-05-18 01:37:23 accepted connection 192.168.0.104:2859
2017-05-18 01:37:23 send version message: version 70002, blocks=0, us=[2001:0:9d38:90d7:28d2:16e:8b98:b88f]:17935, them=0.0.0.0:0, peer=192.168.0.104:17935
2017-05-18 01:37:23 init message: Done loading
2017-05-18 01:37:23 connected to self at 192.168.0.104:2859, disconnecting
2017-05-18 01:37:23 disconnecting node 192.168.0.104:2859
2017-05-18 01:37:23 socket closed
2017-05-18 01:37:23 disconnecting node 192.168.0.104:17935
2017-05-18 01:37:24 refreshWallet
2017-05-18 01:37:25 UPnP: ExternalIPAddress = 192.168.1.100
2017-05-18 01:37:26 UPnP Port Mapping successful.
2017-05-18 01:37:28 connection timeout
2017-05-18 01:37:28 ERROR: GetMyExternalIP() : connection to 216.146.43.70:80 failed
2017-05-18 01:37:29 GetMyExternalIP() received [116.103.71.112] 116.103.71.112:0
2017-05-18 01:37:29 GetMyExternalIP() returned 116.103.71.112
2017-05-18 01:37:29 AddLocal(116.103.71.112:17935,4)