The AmsterdamCoin wallet now has improved connectivity. We have enabled seed node discovery through DNS. This will improve the way how the wallet software finds connections.

In case you are currently stuck, please try this procedure:

1) Backup your wallet
2) Remove all data from the data directory including the wallet
3) Start the wallet software
4) Create a new wallet
5) Let it fully sync
6) Restore your wallet (preferably by using your 12-word seed phrase)