Cannot search footage remotely on internal or extenal ip add

hi, some advise & help please

I have a SHR-6082, it's been set up for around 9 months working fine remotely.

I can view the cctv fine via ip address remotely,

BUT cannot search and view previous cctv remotely.

I could search cctv until now, but recently the search feature does not work, can someone tell me what the fault could be.

Many thanks

pee