Cannot sign a pdf document, saying it has security when there is none

I am trying to sign a document (I was able to do it before) and cannot. The option is greyed out and i cannot add my png image of my signature. However, the properties show it has no security.

Please help me resolve this.

Here is system info:

Account Detail:
User Rights: Admin
User Account Control: Limited
Process Integrity: Medium
Profile Type: None
Acrobat Detail:
Sandboxing: Off
Captive Reader: No
Multi-Reader on Desktop Support: Off
Applications Installed:
Office Version: Office 2016 64-bit
Outlook Version: Outlook 2016 64-bit
Available Physical Memory: 4194303 KB
Available Virtual Memory: 3752936 KB
BIOS Version: ALASKA - 1072009
Default Browser: C:\Program Files\Internet Explorer\iexplore.exe
Version: 11.00.19041.1 (WinBuild.160101.0800)
Creation Date: 2019/12/07
Creation Time: 9:46:23 AM
Default Mail: Microsoft Outlook
mapi32.dll
Version: 1.0.2536.0 (WinBuild.160101.0800)
Creation Date: 2020/08/08
Creation Time: 3:18:35 AM
Display Detail:
Screen Width: 1680
Screen Height: 1050
Number of Monitors: 1
Number of Mouse Buttons: 16
Has Mouse Wheel: Yes
Has Pen Windows: No
Double Byte Character Set: No
Has Input Method Editor: Yes
Inside Screen Reader: No
Graphics Card: AMD Radeon RX 5700 XT
Version: 26.20.13002.133
Check: Not Supported
Installed Acrobat: C:\Program Files (x86)\Adobe\Acrobat DC\Acrobat\Acrobat.exe
Version: 19.21.20058.359605
Creation Date: 2019/12/02
Creation Time: 5:29:28 PM
Locale: English (Canada)
Monitor:
Name: AMD Radeon RX 5700 XT
Resolution: 1680 x 1050 x 60
Bits per pixel: 32
OS Manufacturer: Microsoft Corporation
OS Name: Microsoft Windows 10
OS Version: 10.0.19042
Page File Space: 4194303 KB
Processor: AMD64 Family 23 Model 113 Stepping 0 AuthenticAMD ~3593 Mhz
Session Detail:
Boot Type: Normal
Is Shutting Down: No
Network: Available
Inside Citrix: No
Inside VMWare: No
Remote Session: No
Remote Control: No
Using JAWS: No
Using ZoomText: No
Using Windows-Eyes: No
Using NVDA: No
System Name: NKF-SUPER-PC
Temporary Directory: C:\Users\Natasa\AppData\Local\Temp\
Time Zone: Eastern Standard Time
Total Physical Memory: 4194303 KB
Total Virtual Memory: 4194176 KB
User Name: Natasa
Windows Detail:
Tablet PC: No
Starter Edition: No
Media Center Edition: No
Slow Machine: No
Windows Directory: C:\Windows

Here is plugin info

C:\Program Files (x86)\Adobe\Acrobat DC\Acrobat\plug_ins\Accessibility.api
Version: 19.21.20058.359605
Creation Date: 2019/12/02
Creation Time: 5:29:38 PM
C:\Program Files (x86)\Adobe\Acrobat DC\Acrobat\plug_ins\AcroForm.api
Version: 19.21.20058.359605
Creation Date: 2019/12/02
Creation Time: 5:29:38 PM
C:\Program Files (x86)\Adobe\Acrobat DC\Acrobat\plug_ins\Annots.api
Version: 19.21.20058.359605
Creation Date: 2019/12/02
Creation Time: 5:29:38 PM
C:\Program Files (x86)\Adobe\Acrobat DC\Acrobat\plug_ins\DigSig.api
Version: 19.21.20058.359605
Creation Date: 2019/12/02
Creation Time: 5:29:38 PM
C:\Program Files (x86)\Adobe\Acrobat DC\Acrobat\plug_ins\EScript.api
Version: 19.21.20058.359605
Creation Date: 2019/12/02
Creation Time: 5:29:38 PM
C:\Program Files (x86)\Adobe\Acrobat DC\Acrobat\plug_ins\IA32.api
Version: 19.21.20058.359605
Creation Date: 2019/12/02
Creation Time: 5:29:38 PM
C:\Program Files (x86)\Adobe\Acrobat DC\Acrobat\plug_ins\MakeAccessible.api
Version: 19.21.20058.359605
Creation Date: 2019/12/02
Creation Time: 5:29:38 PM
C:\Program Files (x86)\Adobe\Acrobat DC\Acrobat\plug_ins\PPKLite.api
Version: 19.21.20058.359605
Creation Date: 2019/12/02
Creation Time: 5:29:38 PM
C:\Program Files (x86)\Adobe\Acrobat DC\Acrobat\plug_ins\reflow.api
Version: 19.21.20058.359605
Creation Date: 2019/12/02
Creation Time: 5:29:38 PM
C:\Program Files (x86)\Adobe\Acrobat DC\Acrobat\plug_ins\TouchUp.api
Version: 19.21.20058.359605
Creation Date: 2019/12/02
Creation Time: 5:29:32 PM
C:\Program Files (x86)\Adobe\Acrobat DC\Acrobat\plug_ins\Updater.api
Version: 19.21.20058.359605
Creation Date: 2019/12/02
Creation Time: 5:29:38 PM
C:\Program Files (x86)\Adobe\Acrobat DC\Acrobat\plug_ins\WebPDF.api
Version: 19.21.20058.359605
Creation Date: 2019/12/02
Creation Time: 5:29:38 PM