Error occurred when trying to send rpc requests(s)

[Zephyris94]

Hi,
I am trying to get some blocks using ankr.
While I had some successful calls to ankr net I get an error "Error occurred when trying to send rpc requests(s)"
while trying to get data from block 33796076 to block 33799076
I tried to google the issue and add
System.Net.ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12 | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls;
like it was suggested in another issues on github, but it did not help. I also saw that discussions are usually around Infura but I need ankr for bnb connection
I get the event like this:
var web3 = new Web3(new TimeSpan(1, 0, 0), blockChainAddress);
var transferEvent = web3.Eth.GetEvent(tokenAddress);
I then create a filter input and run it like that
var events = await transferEvent.GetAllChanges(filterInput);
Maybe you could suggest what goes wrong? The weirdes thing is that I initally picked another block and started go adding 3k per cycle, and when I got an exception on 4th cycle I thought that I faced some free plan limitations, but it appeared that issues are with these blocks for instance.
There is no info I can get from this error except 500 internal server error. Can it be THEIR problem on the ankr side?