router problem Why when i turn my router on or restart it it doesnt have internet for the next 40-50 mins but the internet provider says that their network is ok

[Valentin_Tr3yFecta]

When i restart or turn on my router it firstly doesnt have internet connection for the next 40-50 mins.I dialed my internet provider and they said to me that their network is ok and that i have problem with my router