When entering nether portal, established before the update, i fall to my death, there is no nether just bedrock.

I am playing on a private server. we already had a safe entry into the nether setup when the update occurred. After the update, when I try to enter the nether I just fall to my death landing on bedrock. While falling It is dark as if I am in the nether but no nether can be see around me. I dont attempt to walk then fall once i appear in the nether i fall.