Dual band router. Customers iphone and ipad, both can not log onto 2.4. Say wrong password when attempting to join. Both can log onto 5g. Copy pasted all settings making sure both match in router. My phone can log onto both from the start.
Reset network settings on both apple pieces. No go. Create new SSID on 2.4 and keep same password and both now can log onto 2.4. Thoughts from someone with more knowledge.