What is the business impact you are facing? I am unable to complete the transfer of over 20,000 emails from a Gmail account to a new G Suite account using Thunderbird. This issue is causing significant delays in the migration process, impacting the continuity of communication and data management within the business. Issue description I am using Thunderbird to upload emails that were previously downloaded via Google Takeout from a Gmail account to a new G Suite account. The connection to the Gmail IMAP server seems to be correct, as Thunderbird authenticates successfully using OAuth2. However, when attempting to upload the emails, the process stalls. Some emails are uploaded, but many are not, and the upload process stops without providing a clear error message. I need assistance in identifying why Thunderbird is not handling the bulk upload of emails properly and finding a solution to this issue. Connection details with Google: • Server name: imap.gmail.com • Port: 993 • Username: ventas@zeusequipos.com • Authentication method: OAuth2 The connection and authentication work correctly, but the emails do not upload completely. Is it intermittent or consistent? The issue is consistent. It occurs every time I attempt to upload emails in bulk. Steps to reproduce the issue 1. Download emails from a Gmail account using Google Takeout. 2. Attempt to upload the emails to a new G Suite account using Thunderbird. 3. Despite successful authentication and connection with Gmail’s IMAP server, the upload process stalls, and many emails are not uploaded. Browser Not applicable (issue occurs in Thunderbird). Operating system Windows 10. Does clearing cookies, cache, and restarting the browser help? Not applicable (issue occurs in Thunderbird). Does this issue persist in Thunderbird’s safe mode? Yes, the issue persists. Does this issue persist across different computers? Yes, I have tried on another machine, and the issue remains. Does this issue persist across different networks? Yes, the issue persists on a different network.