I socialised him so well, and continue to do so but much less actively I guess. We live rurally but see other dogs most days.
He's always been utterly friendly and outgoing and now suddenly he is wary and even alarm barked at a child bouncing a ball this evening (we were in an unfamiliar place, following a training class so maybe a bit tense anyway).
He's had a few dogs have a bit of a go at him, but not really more than you might expect a very large, boisterous puppy to receive! He just seems to be terribly jumpy now and reactive and suspicious.
Can I resolve this with just active socialisation? I could start to get him meeting loads of friendly dogs and take him to towns to see lots of people. TIA.