Hello, i am not live with my tb shop, but will do this in the near future. I have installed Paypal module and it works fine (in the sandbox text mode), as far as the shop is not live, i can not test it with real customers, but i have several sandbox customers with different Paypal accounts and so there should be no difference.
There are some tb users with problems with Paypal (you can see here in the forum) - not sure about the reason, but it it not very easy to discover these problems, maybe other modules crash something in the payment !?
The best solution seems to install the Mollie payment module, which also accepts Paypal and a lot of other payments. Maybe you will have a look at this module?
Another discussion for Mollie you can find here: https://forum.thirtybees.com/topic/2067/official-mollie-module/32
and maybe you will install this meanwhile and hold your customers. If there is a solution with the normal Paypal module in the next time, you can still test and switch to this later.