SAML broker after successful login POST 405 method not allowed

After successful login on SAML identity provider.
I am receiving next request POST /auth/realms/fuentis HTTP/1.1" 405 from URI.saml.provider

I see that in POST request is missing /auth/realms/fuentis/broker/{alias}/endpoint.
I am not sure what caused this…

Any advice on this

Now, this is only for one particular SAML provider.

For e.g. azure (or some other) as SAML broker things are working OK