Baby naps everywhere but at grandparents

[SleepyMumz]

I've been back at work since the beginning of December and had got baby girl used to napping at my parents and the partners parents.

However the last few weeks when we've taken her to my mum's while we work she has completely skipped her naps. She insists she followed all the instructions but baby just won't sleep and will cry for a whole hour before bringing her back down.
We don't have this problem at all at her other grandparents and it's getting to a point that it's becoming problematic when we collect her, we are at a loss as to why this is only happening there all of a sudden, bedtime setup is the same as at home, blackout blind and white noise.

She sleeps in a travelcot there which she has been fine with in the past, we can't figure out what is going wrong, but my mum understandably feels rubbish that she's only having problems there, does anyone have any insight or advice here?

Will she sleep somewhere else like I'm the pushchair in the hall or if your DM takes her out for a walk?

She does sleep in her pushchair when we're out and about but they're always short naps, she won't sleep in it if the pushchair isn't moving.
But at this stage I'd take a 40 min nap over none at all.
We also use a snoozeshade and portable noise machine for the pushchair, it may be a nuisance for my mum to do that but if it gives her some kind of nap I'll take it