I've help you updated your Payplans Easysocial profile type app instances (SSORG Free , SSWORG Paid) assigned to the proper plan, you can check my attached screenshot below.

Because when i first time subscribe the free plan on your site, it seems like it will assign to the paid profile type during the registration.

Can you give it a try again and see if the issue still persists?

WOW! ok thank you sir!!!
Looks like it's working so far like it should be. I see they cannot join the group, but they can see what people are saying in the group. Is that the way it should be or can it be so they can't see it at all? Meaning they should just be able to see the group picture.http://prntscr.com/m1ir4n. Hope that makes since.

You're most welcome.

Currently I am not sure whether it working or not because i did tried just now, I doesn't receive an email notification for the user account verification code, so can't complete the user verification process.

Have you receive those account verification email notification after you complete the registration?

hmmm no I am not getting any emails.

Can you update your site FTP access so we can better have a check?

By the way, in the future you can just include your site's access once at http://stackideas.com/dashboard/site rather than needing to keep adding them in your replies.

I updated it...ok I changed the warden anti spam rule and they all came through on my side. Recheck yours please, also I see the cron has not run in over 24 hours. Could that be the problem?
http://prntscr.com/m1j47f

It seems like i still not getting any email notification even i register through the Joomla registration page.

To verify this, you can temporary disable this `System-PayPlans` plugin then access this URL [gist type="php"]
https://www.singlesspark.org/index.php?option=com_users&view=registration
[/gist] , and complete the registration field then it will return you this message http://take.ms/RrEA6 .

By right, it should send the user activation mail to me but I already wait 10 minute, it still doesn't send it to me.

I think you have to consult with your webhosting provider regarding this and see whether some where already restricted this?

Because i did tried hotmail and gmail email account also nothing one can receive it.

weird. I am getting the email. http://prntscr.com/m1j5qh
I just forward the email to you tell me if you get it please.
OMG OMG ok found the problem.
https://support.plesk.com/hc/en-us/articles/115000064089

Sure, you can forward to my email arlex.wong@stackideas.com

Based on what i see this email only notify to your site Superadmin , and what i mean is I am not getting the user activation email.

If this user 'webmaster@redtalkers.net' is your test email, perhaps you can try delete this user account from your site backend then do following step and see how it goes.

1. Temporary disable this `System-PayPlans` plugin from your backend plugin manager

2. Access this page as a guest user
[gist type="php"]
https://www.singlesspark.org/index.php?option=com_users&view=registration
[/gist]

3. Complete that Joomla registration form then you will get this message http://take.ms/RrEA6 .

4. Check your mailbox (webmaster@redtalkers.net) and see whether you did receive activation email.

This looks correct:
[root@513DC79 /]# dig singlesspark.org +short
104.219.41.186
[root@513DC79 /]# dig singlesspark.org mx +short
10 mail.singlesspark.org.
[root@513DC79 /]#

I just did a test email from the global config. I just emailed it to you

added a few nameserver 8.8.8.8
did a postsuper -r ALL

Tell me if you get it please.

Hey Richard,

Do you mean you have forward those email to my mail account arlex.wong@stackideas.com?

Because i did checked my mailbox, I doesn't receive your forward email.

By the way, I did a test again, it seems I still unable to get the user activation email.

Front end with test account set to free account
http://prntscr.com/m1fgy7 ( I can still join the group)

Perhaps you can try test with your initially issue and see if those test account still can able to join the group?

If they still can able to join the group, can you provide us that test account access so we can better have a check?