We have encountered the exact same error with a fresh install of Windows 11 Pro using Quickbooks 2022 and having Microsoft Office 2022.  We kept receiving the QBmapi64 error and would not send invoices after 4-5 were sent.  We have done a variety of troubleshooting and even ran the QBmapi64 program in Administrator mode, rebooted and the error reappeared after the restart of Quickbooks and sending 4-5 more invoices.  We even increased the virtual memory to 20GB to help with memory cache for the emails and that barely seemed to help.