If your skin resistance with foot grounders or ESD shoes is high, how can you get the skin resistance down?
Are there any brands of ESD socks that are good?
It may be that the skin is very dry. Is this a single person or all the people? If it is a single person, try walking around for 10 min and retest. Sometimes is takes a few minutes for some people to make that connection.
If they are using foot grounders, try to put the contact strip under the foot and in contact with the skin. This may also solve the problem.
This is a common problem, especially in the winter season when many areas are more dry. The moisture a person generates helps create the electrical contact needed for ESD footwear to be the most effective. While some persons create this easily, others may struggle. As suggested, sometimes simply walking for 10 or 15 minutes is sufficient. If using foot straps, place the strap directly against the skin rather than outside of the sock to minimize the moisture required to make good contact. Even then, I have seen where persons had to apply lotion and or water and dampen their feet to make proper contact.