Update your wallet to the latest version (v1.0.0.5).
Older wallets will no longer be able to connect to the blockchain due to a change in network protocol that came into effect at 00:00:00 (UTC) Jan 2nd 2018.
Do not try to make any transactions if you are still using the old wallet (v0.9.0.2) as they may be lost.
Download for WIN, OSX and Ubuntu here : https://mylinx.io/downloads
Compile from source yourself here : https://github.com/linx-project/linx