I have had issues with a vlan setup after adding a 3rd switch.  

I have a TL-SG1024DE switch that has vlans attached to it.  Port 1 is connected to wifi router and untagged in all of the VLANs.  Ports 2 and 3 are connected to two TL-SG108E switches.  Both ports 2 and 3 are tagged in all the VLANs.  Ports for the 3 vlans are untagged.   In the pvid config ports 1,2 and 3 are in 1.  The other ports are are part of their respective vlans.   On the two TL-SG108E switches port 1 is connected to the 24 port switch.  Port 1 is tagged in all the VLANs and all other ports are untagged in their respective VLANs.   PVID is configured with port 1 is is 1 and the other the respective VLANs.  It works for then everything loses connection to wifi router.   It seems to come and go with no reason.   The setup was working with only one 8 port switch connected to the 24 port switch.  When I add the configuration for the 2nd 8 port switch all the issues begin.   If I turn the VLAN off then everything has no connection issue.  Is there a confesses here or is this possibly a hardware issue with one or more of the switches?