There has been relatively little fighting in the southern Balkans over the last number of months. The Germans have been content to leave the Allies alone in Salonika while the Allied force there has not been strong enough to attempt a push north. Disease has taken more of a toll on both sides than the efforts of their enemies.
Now though the British make an attempt to push north against the Bulgarians holding the line against them. Attacking near Doiran, the British make some initial gains. However the Bulgarian defence under General Vasov is dogged; they are also favoured by the terrain. The British advance is contained, with Bulgarian counterattacks recovering many of the positions lost. Any dreams of an Allied breakthrough in the Balkans remain unrealised.
image source: Vladimir Vasov (Wikipedia)