Cell phone is ONLY my Wi-Fi not anymore?

I have a Vodafon router where my internet worked perfectly for weeks on the PC, Xbox One, my laptop and my cell phone. Xbox, laptop and mobile phone, of course, with wireless internet. One day I came home and since then my mobile phone can no longer find the Wi-Fi. Everything else works and my mobile phone also finds all other wireless networks. What happened and what can I do? Someone an idea?

Delete your saved WLAN profile on the phone and then try again, even router and cell phone restart

Everything already tried, also reset my complete mobile phone.