Imap extension install and deleted disabled function still not working

aaP_keshav_singh4

i am trying to install acellemail. which require imap. and its not working.
Using php 7, negix, unbuntu.

no imap_open function found.

aaPanel_Kern

Hi, can you give us your aapanel information? The server makes a snapshot backup first, if possible, please send it to kern@aapanel.com.
It is recommended to fill in the following
Post link:
SSH IP address, account password and port:
aapanel login link address and account password:
Detailed problem description:

No post link will not be able to know which user's information is, and the problem will not be processed

aaP_keshav_singh4