Email is not working

I have website hosted on linode and domain is from namecheap and email is hosted on namecheap. but wordpress default email is not working i also talked with namecheap there is all things perfect from cyberpanel side something is problematic like 465 port is not open showing this error. image hosted at ImgBB — ImgBB

I’m using mailster plugin and showing me this image hosted at ImgBB — ImgBB error so i’m unable to using this even default wordpress email is not working

@neweracloud said:
Try a plugin > Search Results for “smpt” | WordPress.org

even i have tried with one plugin but not working please check what mailster showing errors. image hosted at ImgBB — ImgBB