为什么下面的代码反复给我一个错误？

library(rcrossref) 
library(rAltmetric)

alt <- altmetrics(doi = '10.1111/j.1475-2743.2006.00029.x')
Error: lexical error: invalid char in json text.
                                       The API key you supplied was no
                     (right here) ------^
In addition: Warning message:
In altmetrics(doi = "10.1111/j.1475-2743.2006.00029.x") :
  Unauthorized (HTTP 401).

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