Expired email certificate e

Hello Laurence,
I understand the inconvenience caused. I have sent you an email, please reply to my email with the requested information to assist you further.
Best regards,
Alok.

Hi. I use outlook 2016.  I have 3 different inboxes with 3 different providers all configured on IMAP.
Every few months - after opening outlook, i'm presented with an errror message that an AVG security certificate has expired, for one of the email domain accounts.

the error says: the server you are connected to is using a security certificate that cannot be verified.
i click View Certificate:
issued to  mail.{mydomainname}.com  
issued by  AVG web/mail shield root
valid from  16/01/18 to 16/04/18

Who is issuing the certificate? how do I resolve? all my domain and web is all through AWS/Rainloop and was setup for me.

thanks

Hello Laurence,
I understand the inconvenience caused. I have sent you an email, please reply to my email with the requested information to assist you further.
Best regards,
Alok.