hmrc app pin problem

have tried to set up hmrc app, got access etc, set up six digit pin for access (entering it twice as requested) however it doesnt seem to save that just carries on to fingerprint id which i say not now to. when i go to log in again it doesnt give the pin option that i want, i have to go through the full details again. my partner is able to log in just with the pin. can you help please

Hi,
Please contact Technical support with HMRC online services.
Thank you.