There is an issue with WLED versions >0.13.2 in connection with some FritzBoxes with SW >=7.50 and possibly with the activated mesh. The WLED controller sometimes restarts every minute. A possible solution (but probably not 100%) is to deactivate UPnP in the FritzBox settings (under home network -> network -> network settings -> other settings -> transfer status information via UPnP). Another possible measure is to deactivate mDNS in WLED settings (delete mDNS name). The issue may also affect some UniFi devices with mesh activated. Currently, a WLED software build based on ESP IDF V4 is recommended to solve the problem.