Not getting e-mails anymore

[hlmeier]

Hello! I just recently noticed my Samsung Exhibit is no longer receiving my e-mails through my school account, which is my main e-mail account. When I go to check the account settings, it's the incoming serving setting that is having problems. It comes up with this error:
Cannot safely connect to server. (org.bouncycastle.jce.exception.ExtCertPathValidatorException: Could not validate certificate signature.)

My e-mail has worked just fine up until now. I don't know what needs to be changed in order to receive my e-mails again. I tried remaking the account and it would not connect that way either. I'm just lost right now and could really use some help.

 

[clodfelterac]

resync?... reboot?... are you rooted?...

 

[hlmeier]

I can't resync for some reason. My account doesn't show up. It might be because it's not yahoo or anything like that, it's my school e-mail. I've also rebooted since the problem and it did nothing. I don't know what rooted means. I'm not super tech savvy, but I can get things fixed for the most part. This is the first real problem I've had I can't fix on my own.