Manual redirect

Hello everyone. I have a problem with this page that is 404: https://explicativ.ro/definitie-dex-sufoziune/c and the original and logical redirect will be to https://explicativ.ro/definitie-dex-sufoziune/, but this is not happening. I tried in exemple mode and the exemple is ok, but in reality he redirect to this page: https://explicativ.ro/cabluri-rezistente-la-incendiu-ce-sunt-si-cum-alegi-cele-mai-bune-optiuni/

My qquescion is, i can do something manually to fix it? I have a very important link to that 404 page and i dont want to lose it. Thank you.

The page I need help with: [log in to see the link]