My Thunderbird email works perfectly when the PC is connected to a network by WiFi or cable. But when I connect the PC to the internet via the 'Personal Hotspot' (shared internet) function on my iPhone, I can only receive emails, not send emails. See attached screenshots of the error message and account settings. I use Thunderbird version 91.9.0 (64-bit), and Windows 11 Home version 21H2. Windows Security for antivirus and firewall. Mail provider is domeneshop.no.