If a report does not send

Troubleshooting

Each way of sending fails in its own way. Find yours, and keep 'Copy as Markdown' as a way that always works.

Steps

GitHub opens in the same tab: the browser blocked a new tab, so Snaglist used this one. Use the browser's Back to return. To have a new tab, allow pop-ups for the site.
GitHub opens with an empty report: the report was too long for a web address and is on your clipboard. Paste it into the issue.
Labels are missing on GitHub: GitHub only adds labels that exist, and only for people who may label issues. Read Send reports to GitHub.
This computer is not online: select Show as a QR code and scan it with your phone. Read Send a report with a QR code.
Open in email does nothing: no mail app is set up on this computer. Use Copy as Markdown and paste the report into an email.
Send says "Not sent": the message after it gives the reason. A number such as 403 or 500 comes from the site's server; "Failed to fetch" usually means the server did not allow the request from this site. Read step 3 of Send reports to your own server.