Hi LindyMH,
Thanks for your post. This can be quite tricky. A viable workaround, if you're working with an online file, is to use the online emailing function instead of Outlook.However, there are a range of interop errors that can often be fixed by one of the following:
A. Quick Repair Office (any missing files should be added back)
B. Re-register Outlook DLL files and check/fix registry keys (there are three to complete)
Other solutions may require an IT specialist. Please see this help page for more information. https://webmakers.co.nz/interface-not-registered-exception-from-hresult-0x80040155-microsoft-office-outlook-error/
Feel free to post again, we're happy to help!
Regards,
Earl