@Rostislav_74 Hi you try to ether install beta or downgrade to previous stable firmware. See thread: https://community.tp-link.com/en/home/forum/topic/703810.

@David-TP Thanks for your answer and explanations. I'll consider to switch to a dynamic IP system and change my NAS IP although it will be trouble some with so many devices connected via SMB. For the...

@David-TP Hi, thanks for the answer. My NAS got a fix IP in lower range than DHCP server that can be reserved. Anyway I'll consider to change it. About the connection, in despite IPv4 is static, my...

@David-TP Hi David, no static IP configuration is not required by my ISP. Actually I'm using such type to keep the NAS for SMB access in my home network. About the manual DNS, I've chosen...

@David-TP Hi, as answered by email: ISP: Telefonica-Movistar. IPv4: Static IP. Really wish to change the actual firmware which is causing a big mess at home!!

@David-TP Hi David, I've got same issue since last upgrade to 1.5.5 (Deco X50 v1.0). Can you send me the new beta firmware to try?