Adding an attachment control to a Custom Form in SharePoint 2016 on Premises

[mwilliams71]

I've created a custom form, but the attachment button on the Ribbon is disabled. So I added an attachment button to the custom form and I'm getting the error of "Uncaught TypeError: Cannot read properties of null (reading 'insertRow')"

I used this article, but I'm getting the error above.

https://www.c-sharpcorner.com/article/upload-file-to-listitem-in-office-365-as-an-attachment-using-j...

[#2]

Which browser are you using? Can you try another one?

[#3]

Thank you for the quick response Joao. I'm using Edge. Let me try Firefox.

[#4]

Hello Joao. I tried Edge, FireFox, and IE. Neither works for me. The attachment button on the Ribbon does not work and the custom solution mention above, does not add the attachment.

[#5]

I get the error:
Request failed with error message - File Not Found. Stack Trace - undefined

[#6]

Can you share your code? Let me see the html