The website URL you provided https://arcor.log-in.de.com/ appears to be suspicious and potentially a phishing or scam site, as it mimics the format of legitimate domains (like Arcor or Deutsche Telekom) but uses a deceptive subdomain structure (log-in.de.com). For your safety, do not enter any personal information or login credentials on that site. Always verify official domains directly (e.g., arcor.de or telekom.de). If you received this link through email or message, it's best to ignore it and report it as phishing. Cybercriminals often create such fake login pages to steal passwords and personal data. Stay vigilant online.