If you have PDFs with fillable fields signed externally (outside of RentRedi), you will to export as a PDF without fillable form fields before uploading them to RentRedi.
Export from Adobe Acrobat, Preview, (or similar) as a read-only (or static) PDF without fillable form fields.
Open the PDF file in Preview that you want to make static. If you have another app set to open your PDF files, simply right-click the file and select Preview from the Open with menu.
From the File menu, select the “Export to PDF” option.
Save the file
For Adobe Acrobat Pro*:
Save a copy of the PDF
Open the copy of the PDF
Save As Optimized PDF
Go to Discard Objects
Check Flatten Form Fields box
Click on Okay to save as a regular uneditable PDF