First of all I would recommend you to contact your App developer. Normally they have experience with these type of issues. Also it looks that you are not the only one with this issue as a Google search even resulted some websites with this error live on their website.
I would check on line 297 of the theme.liquid file to see if you can maybe remove the code that is requesting the file or comment it out. If the app works, then apparently the code is not critical.
If you have any other questions, please feel free to let me know.
Best wishes, Thom Knepper - Athom.Agency - Was my reply helpful? Please Like to let me know! - Was your question answered? Awesome! Please Mark it as an Accepted Solution