The problem at T-Mobile has been resolved.
Due to the defect, companies and local authorities had to deal with telephone problems for hours on Tuesday morning.
Incoming and outgoing calls were sometimes not possible.
It is not yet clear what caused the outage.
The provincial government of Drenthe, municipalities such as Zwolle and Veenendaal and the Zeeland Adrz hospital were not or only poorly accessible due to the problems.
This also applied to the ANWB, the courts and the Central Judicial Collection Agency (CJIB).
Various organisations, including the ANWB, the Midden-Nederland court and travel group TUI Nederland, have already announced via Twitter that they are no longer affected by the malfunction.
In parts of the country, the police already had to deal with a technical malfunction during the night from Monday to Tuesday at the telephone number for non-emergency matters, 0900-8844.
The number was temporarily unavailable.
In any case, it concerned the regions of Rotterdam, Utrecht, Flevoland and Gooi en Vechtstreek that reported on Twitter that there was a malfunction.
Shortly before 6.30 am it was reported that the problems in Utrecht, Flevoland and Gooi- en Vechtstreek were over.
At 07:30 am, the Rotterdam police also reported that the "non-emergency line" was available again.
The emergency number 112 was reachable.