Grateful for any advice. Puppy is 16 weeks old and has been trained to toilet on a grass potty patch - we have fresh turf delivered weekly as we live in an apartment. He's been walking outside now for two weeks post vaccines and isn't showing any interest in toileting outside. I put him on grass outside and use the command 'toilet' but nothing. I've put a grass potty patch in our communal outdoor area in the hope he'll first go there and nothing. This morning rather than open the door to the terrace and potty I took him straight down to the other potty I'd put down there and nothing. I took him for a short walk thinking he'd be busting and go, onto grass by the river again saying toiLet but nothing. As soon as we got home he peed on the chair so he WAS busting. We've taken him out for the day with more commands on more grass and nothing and he held it in for HOURS. I feel terrible, be must have been so uncomfortable. Does anyone have advice please?