Can't connect with some clients

[Emiliano Gonzalez]

I have a ssh server.

When I connect with the client on Fedora 32 ssh there are no problems.

With PuTTY: Release 0.74 I can't connect with error: Couldn't agree a host
key algorithm (available: rsa-sha2-512, rsa-sha2-256)

>From Centos 7 ssh server crash. In packet.c (line 1862):

    /* For smaller blocks use limit of 1 GB as recommended in RFC4253 */
    cipher->max_blocks = ((uint64_t)1 << 30) / cipher->blocksize;

cipher->blocksize is 0;