Too many 500 error responses while setting reverse-dns

I am trying to setup reverse-dns for one of my public ips but I am getting this error:

request failed: Error occurred in request., RetryError: HTTPSConnectionPool(host='management.azure.com', port=443): Max retries exceeded with url: /subscriptions/xxxxxx/resourceGroups/xxxxx/providers/Microsoft.Network/publicIPAddresses/xxxx?api-version=2019-04-01 (Caused by ResponseError('too many 500 error responses',))

This is the command I am using (I already have a DNS label setup):

az network public-ip update --resource-group xxxx --name xxxx --reverse-fqdn xxxx

Please help. Thanks!

I replaced the original values by xxxx ;)