Actually, here is the error:
/ssl openssl x509 -inform der -in site_ru.crt -out site_ru.pem unable to load certificate 140451851716160:error:0D0680A8:asn1 encoding routines:asn1_check_tlen:wrong tag:../crypto/asn1/tasn_dec.c:1130: 140451851716160:error:0D07803A:asn1 encoding routines:asn1_item_embed_d2i:nested asn1 error:../crypto/asn1/tasn_dec.c:290:Type=X509 There are no extra characters, neither at the beginning nor at the end:
/ssl xxd -l 10 site_ru.crt 00000000: 2d2d 2d2d 2d42 4547 494e -----BEGIN