Error(s) in re-building vignettes:
  ...
duplicated vignette title:
  ‘Retrieving and Analyzing PubMed Records via easyPubMed’

--- re-building ‘easyPM_vignette_html.Rmd’ using rmarkdown
Warning in grep("\\\n$", msg) :
  input string 1 is invalid in this locale
Quitting from lines 39-50 (easyPM_vignette_html.Rmd) 
Error: processing vignette 'easyPM_vignette_html.Rmd' failed with diagnostics:
1: Input is not proper UTF-8, indicate encoding !
Bytes: 0xF0 0x86 0x5A 0xAA
2: error parsing attribute name
3: attributes construct error
4: Couldn't find end of Start Tag C<f0> line 784
5: Opening and ending tag mismatch: Reference line 810 and ArticleIdList
6: Opening and ending tag mismatch: ReferenceList line 740 and Reference
7: Opening and ending tag mismatch: PubmedData line 698 and ReferenceList
8: Opening and ending tag mismatch: PubmedArticle line 443 and PubmedData
9: Opening and ending tag mismatch: PubmedArticleSet line 3 and PubmedArticle
10: Extra content at the end of the document

--- failed re-building ‘easyPM_vignette_html.Rmd’

--- re-building ‘easyPM_vignette_pdf.Rmd’ using rmarkdown
Warning in for (i in seq_len(n)) { :
  closing unused connection 5 (https://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?db=pubmed&WebEnv=NCID_1_99937168_130.14.22.32_9001_1546279535_1303607976_0MetA0_S_MegaStore&query_key=1&retstart=0&retmax=500&rettype=null&retmode=xml)
Warning in grep("\\\n$", msg) :
  input string 1 is invalid in this locale
Quitting from lines 39-50 (easyPM_vignette_pdf.Rmd) 
Error: processing vignette 'easyPM_vignette_pdf.Rmd' failed with diagnostics:
1: Input is not proper UTF-8, indicate encoding !
Bytes: 0xF0 0x63 0x27 0xFE
2: error parsing attribute name
3: attributes construct error
4: Couldn't find end of Start Tag C<f0>c line 784
5: PCDATA invalid Char value 16
6: PCDATA invalid Char value 6
7: PCDATA invalid Char value 1
8: PCDATA invalid Char value 1
9: PCDATA invalid Char value 5
10: PCDATA invalid Char value 5
11: PCDATA invalid Char value 19
12: PCDATA invalid Char value 17
13: PCDATA invalid Char value 6
14: PCDATA invalid Char value 3
15: PCDATA invalid Char value 4
16: PCDATA invalid Char value 3
17: PCDATA invalid Char value 19
18: PCDATA invalid Char value 30
19: PCDATA invalid Char value 30
20: PCDATA invalid Char value 23
21: PCDATA invalid Char value 23
22: PCDATA invalid Char value 11
23: PCDATA invalid Char value 6
24: PCDATA invalid Char value 3
25: PCDATA invalid Char value 4
26: PCDATA invalid Char value 6
27: PCDATA invalid Char value 19
28: PCDATA invalid Char value 2
29: PCDATA invalid Char value 27
30: PCDATA invalid Char value 25
31: PCDATA invalid Char value 6
32: PCDATA invalid Char value 3
33: PCDATA invalid Char value 4
34: PCDATA invalid Char value 8
35: PCDATA invalid Char value 19
36: PCDATA invalid Char value 18
37: PCDATA invalid Char value 16
38: PCDATA invalid Char value 14
39: PCDATA invalid Char value 6
40: PCDATA invalid Char value 3
41: PCDATA invalid Char value 4
42: PCDATA invalid Char value 7
43: PCDATA invalid Char value 19
44: PCDATA invalid Char value 7
45: PCDATA invalid Char value 26
46: PCDATA invalid Char value 24
47: PCDATA invalid Char value 6
48: PCDATA invalid Char value 3
49: PCDATA invalid Char value 4
50: PCDATA invalid Char value 19
51: PCDATA invalid Char value 17
52: PCDATA invalid Char value 6
53: PCDATA invalid Char value 3
54: PCDATA invalid Char value 4
55: PCDATA invalid Char value 3
56: PCDATA invalid Char value 19
57: PCDATA invalid Char value 30
58: PCDATA invalid Char value 1
59: PCDATA invalid Char value 6
60: PCDATA invalid Char value 1
61: PCDATA invalid Char value 1
62: PCDATA invalid Char value 1
63: PCDATA invalid Char value 5
64: PCDATA invalid Char value 2
65: PCDATA invalid Char value 1
66: PCDATA invalid Char value 1
67: PCDATA invalid Char value 6
68: StartTag: invalid element name
69: PCDATA invalid Char value 28
70: PCDATA invalid Char value 22
71: PCDATA invalid Char value 22
72: PCDATA invalid Char value 21
73: xmlParseEntityRef: no name
74: PCDATA invalid Char value 24
75: PCDATA invalid Char value 4
76: PCDATA invalid Char value 2
77: xmlParseEntityRef: no name
78: PCDATA invalid Char value 29
79: PCDATA invalid Char value 11
80: PCDATA invalid Char value 5
81: PCDATA invalid Char value 25
82: PCDATA invalid Char value 5
83: PCDATA invalid Char value 7
84: PCDATA invalid Char value 25
85: PCDATA invalid Char value 18
86: PCDATA invalid Char value 4
87: xmlParseEntityRef: no name
88: PCDATA invalid Char value 2
89: PCDATA invalid Char value 3
90: PCDATA invalid Char value 1
91: PCDATA invalid Char value 6
92: PCDATA invalid Char value 1
93: PCDATA invalid Char value 1
94: PCDATA invalid Char value 5
95: PCDATA invalid Char value 5
96: PCDATA invalid Char value 2
97: PCDATA invalid Char value 7
98: PCDATA invalid Char value 8
99: PCDATA invalid Char value 30
100: PCDATA invalid Char value 5
101: PCDATA invalid Char value 23
102: PCDATA invalid Char value 30
103: PCDATA invalid Char value 1
104: Opening and ending tag mismatch: Author line 2336 and AffiliationInfo
105: Opening and ending tag mismatch: AuthorList line 2308 and Author
106: Opening and ending tag mismatch: Article line 2284 and AuthorList
107: Opening and ending tag mismatch: MedlineCitation line 2272 and Article
108: Opening and ending tag mismatch: PubmedArticle line 2271 and MedlineCitation
109: Opening and ending tag mismatch: PubmedArticleSet line 3 and PubmedArticle
110: Extra content at the end of the document

--- failed re-building ‘easyPM_vignette_pdf.Rmd’

SUMMARY: processing the following files failed:
  ‘easyPM_vignette_html.Rmd’ ‘easyPM_vignette_pdf.Rmd’

Error: Vignette re-building failed.
Error: Duplicate vignette titles.
  Ensure that the %\VignetteIndexEntry lines in the vignette sources
  correspond to the vignette titles.
Execution halted