Spots on lawn where moss was lawn seed hasnt germinated on

Hi
In Spring time I put down moss killer to kill off moss on parts of the lawn
When it had died - i raked it out, aerated the soil and planted lawn seed that i mixed with compost and watered
Nothing has grown in those spots at all
They look like attached
As you can see the lawn is quite healthy where grass is growing a
Any suggestions what i could do to fix this
Thanks

 

Hi, perhaps there was some residual moss killer still there, i would try again this autumn.