CentOS 7 - Update impossible

Hello,
on my CentOS 7 system in a VirtualBox the Update is impossible.
Code:$ sudo dnf update -y
...
Gesamt 695 MB/s | 549 MB 00:00
Warnung: /var/cache/dnf/google-chrome-6ed7e4f336f6863c/packages/google-chrome-stable-115.0.5790.170-1.x86_64.rpm: Header V4 RSA/SHA512 Signature, Schlissel-ID a3b88b8b: NOKEY
google-chrome 0.0 B/s | 0 B 00:00
GPG-Schlissel unter https://dl.google.com/linux/linux_signing_key.pub (0x7FAC5991) ist bereits installiert
GPG-Schlissel unter https://dl.google.com/linux/linux_signing_key.pub (0xD38B4796) ist bereits installiert
Die heruntergeladenen Pakete wurden bis zur nichsten erfolgreichen Transaktion im Zwischenspeicher abgelegt.
Sie kinnen zwischengespeicherte Pakete mit dem Befehl idnf clean packagesi entfernen.
Traceback (most recent call last):
File "/bin/dnf", line 58, in <module>
main.user_main(sys.argv[1:], exit_code=True)
File "/usr/lib/python2.7/site-packages/dnf/cli/main.py", line 179, in user_main
errcode = main(args)
File "/usr/lib/python2.7/site-packages/dnf/cli/main.py", line 64, in main
return _main(base, args, cli_class, option_parser_class)
File "/usr/lib/python2.7/site-packages/dnf/cli/main.py", line 99, in _main
return cli_run(cli, base)
File "/usr/lib/python2.7/site-packages/dnf/cli/main.py", line 123, in cli_run
ret = resolving(cli, base)
File "/usr/lib/python2.7/site-packages/dnf/cli/main.py", line 154, in resolving
base.do_transaction(display=displays)
File "/usr/lib/python2.7/site-packages/dnf/cli/cli.py", line 232, in do_transaction
self.gpgsigcheck(install_pkgs)
File "/usr/lib/python2.7/site-packages/dnf/cli/cli.py", line 286, in gpgsigcheck
error_messages.append(str(e))
UnicodeEncodeError: 'ascii' codec can't encode character u'\xfc' in position 26: ordinal not in range(128)How can I repair this situation?

with regards
Ch. Hanisch