I have coded a webpart using SPFx framework, and am trying to add the webpart into the page layout to avoid any changes by the users. The site is using Classic Experience, and I have coded the Master Page and Page Layout with the help of Design Manager.
As per Hardcoding a Webpart in Page Layout, I have exported the webpart, and upload it to the Webpart Gallery. However, when I go to my Page Layout->Snippets, and after selecting my uploaded webpart, it returns the following error
Cannot create an object of type 'System.Collections.Generic.List`1[[System.String, mscorlib, Version=188.8.131.52, Culture=neutral, PublicKeyToken=b77a5c561934e089]]
I also noted that Billy has encountered the same error at Is there any way to have a static custom made SPFx web-part in a page-layout template you have created in Design manager (Sharepoint Online)?