Mail Application crashes when I open the App

I turn on my mac, click the mail app icon and message screen appears saying that "Mail quit unexpectedly while using the Mail plug-in."

Here are the other details found in the message screen:

Process: Mail [685]

Path: /Applications/Mail.app/Contents/MacOS/Mail

Identifier: com.apple.mail

Version: 10.1 (3251)

Build Info: Mail-3251000000000000~1

Code Type: X86-64 (Native)

Parent Process: ??? [1]

Responsible: Mail [685]

User ID: 502

PlugIn Path: /System/Library/PrivateFrameworks/Mail.framework/Versions/A/Mail

PlugIn Identifier: com.apple.Mail.framework

PlugIn Version: 10.1 (3251)

Date/Time: 2016-11-24 06:49:55.349 +0800

OS Version: Mac OS X 10.12.1 (16B2657)

Report Version: 12

Anonymous UUID: 2F1DED91-6355-352E-3829-CDDDEB9A1C40

Time Awake Since Boot: 110 seconds

System Integrity Protection: enabled

Crashed Thread: 0 Dispatch queue: com.apple.main-thread

Exception Type: EXC_BAD_ACCESS (Code Signature Invalid)

Exception Codes: 0x0000000000000032, 0x00007fffc9fcba88

Exception Note: EXC_CORPSE_NOTIFY

Termination Reason: Namespace CODESIGNING, Code 0x2

I updated to macOS Sierra a week or so ago and did not experience this until today. Would appreciate any help as I heavily rely on the Mail application.

Thank you!