Problem: You install a third party plugin like phpBB or WordPress onto an aMember install that has existing users. The goal is to now have these users access the forum or WordPress but users do not have access, no users are added to the script.
Solution: After installing the plugin, you must click on Rebuild Database to populate the 3rd party script with your existing users.
Be aware that sometimes Database Rebuilds can also revoke access to some products especially if you changed the product configuration. This is not a bug but likely a product configuration. If you get a lot of support tickets where people suddenly cannot access other products after the database rebuilds it is likely because of the re-build. There is no way to return to the old way the only way to fix it is to go to the product(s) in question, fix the access there and re-build again.