Recieve CA Root Certificate not installed when trying to open attachments in email?

[AC Question]

Cant open attachments or reply to any emails from my work on my phone. I can respond from home PC. Other emails with attachments from other emails i can open and reply to. I get a a notification whenever it fails that says CA Root Certificate not installed, I never had a problem with this it just started maybe 2 weeks. I really would appreciate any input. PS...my provider was no help

 

[itguyjax8430]

Cant open attachments or reply to any emails from my work on my phone. I can respond from home PC. Other emails with attachments from other emails i can open and reply to. I get a a notification whenever it fails that says CA Root Certificate not installed, I never had a problem with this it just started maybe 2 weeks. I really would appreciate any input. PS...my provider was no help

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Are the emails digitally signed or anything like that?

 

[IVLogan]

Yes but I didnt have this problem 2 weeks ago. Can view plain text from same emails. Anything with an Attachment I have to verify Signature and then Ill get the error message. TY for any advice

 

[sheyo]

I've been having the same/or similar issues since the first Marshmallow update. Anytime I receive an email with a digital signature (in this case a DOD signature), I cannot verify the signature ... and, thus, cannot open any associated attachments. It does not matter what type of attachment it is. I have attempted to install the DOD root certs and still cannot open the emails. It worked fine before the update.