Some customer cannot login after register

[Joey]

I have a multistore Prestashop store running 1.6.1.7 Https://www.sweetwedding.com.hk and currently half of clients complain that they can't login the store after register but I can see their customer profile was created successfully in BO. I am currently unable to pinpoint the issue but I think it might be something with the cookies or the login module of the store. 

However some clients are able to enter and some are not and this is across multiple browsers, not only one. Mostly I asked the customer to use another computer or mobile or clear the browser cache can solve this problem. But it was hard to ask each customer to clear their browser cache and some of customer don’t know how to do that and need a lot of time to teach them, it will lost lot of customer as they feel trouble!

 

i did following in back office but the issue still same :

1. Clear all cache

2. Disable cache

3. Recompile all program

4. Install php difference version on Linux 

 

[NemoPS]

I wonder if it's getting stuck when assigning the store id. Are you sharing customers between stores?