I am trying to upload wsp solution to Office 365 in Solution Gallery but It's throwing error
Sorry, something went wrong
The request could not be completed because the specified solution was not found.
Same wsp solution is uploading and activating to another site collection and other tenant but not deploying in my root site collection in Office365.
EDIT: Even when I am uploading any file to Site Pages library or changing the welcome page of the site, this error occurs.
And even from SharePoint Designer I am unable to change my welcome page and uploading any file to library.
Any solution ?