Reports like yours are becoming very common. I have not see a definitive solution for the problem. But Apple server maintenance may be what is causing it. A few days ago I saw a post indicating that, per an Apple tech, Apple is conducting major [server] maintenance and that many services are down. The instruction given was to "try again tomorrow ... [and] maybe the [needed] server will be back online.
You can get Apple telephone support for help with the problem using this link https://getsupport.apple.com/?caller=kbase&PGF=PGF63005&category_id=SC0245&symptom_id=23362 Be patient sometimes Apple support is closed to immediate phone support.
And here is how to contact iTunes worldwide support via text or chat using this link https://support.apple.com/choose-country-region/itunes. After choosing your country, see the heading Tell us how we can help.