convert does not read pdf fiile

calibre, version 3.22.1 (win32, embedded-python: True)
Conversion error: Failed: Convert book 1 of 1 (Planetary Nebulae and How to Observe Them)

Convert book 1 of 1 (Planetary Nebulae and How to Observe Them)
Conversion options changed from defaults:
  verbose: 2
  read_metadata_from_opf: u'C:\\Users\\Student\\AppData\\Local\\Temp\\calibre_3nkkvk\\lylox9.opf'
  output_profile: 'kindle_pw'
Resolved conversion options
calibre version: 3.22.1
{'asciiize': False,
 'author_sort': None,
 'authors': None,
 'base_font_size': 0.0,
 'book_producer': None,
 'change_justification': u'original',
 'chapter': u"//*[((name()='h1' or name()='h2') and re:test(., '\\s*((chapter|book|section|part)\\s+)|((prolog|prologue|epilogue)(\\s+|$))', 'i')) or @class = 'chapter']",
 'chapter_mark': u'pagebreak',
 'comments': None,
 'cover': None,
 'debug_pipeline': None,
 'dehyphenate': True,
 'delete_blank_paragraphs': True,
 'disable_font_rescaling': False,
 'dont_compress': False,
 'duplicate_links_in_toc': False,
 'embed_all_fonts': False,
 'embed_font_family': None,
 'enable_heuristics': False,
 'expand_css': False,
 'extra_css': None,
 'extract_to': None,
 'filter_css': u'',
 'fix_indents': True,
 'font_size_mapping': None,
 'format_scene_breaks': True,
 'html_unwrap_factor': 0.4,
 'input_encoding': None,
 'input_profile': <calibre.customize.profiles.InputProfile object at 0x03CC5E10>,
 'insert_blank_line': False,
 'insert_blank_line_size': 0.5,
 'insert_metadata': False,
 'isbn': None,
 'italicize_common_cases': True,
 'keep_ligatures': False,
 'language': None,
 'level1_toc': None,
 'level2_toc': None,
 'level3_toc': None,
 'line_height': 0.0,
 'linearize_tables': False,
 'margin_bottom': 5.0,
 'margin_left': 5.0,
 'margin_right': 5.0,
 'margin_top': 5.0,
 'markup_chapter_headings': True,
 'max_toc_links': 50,
 'minimum_line_height': 120.0,
 'mobi_file_type': u'old',
 'mobi_ignore_margins': False,
 'mobi_keep_original_images': False,
 'mobi_toc_at_start': False,
 'new_pdf_engine': False,
 'no_chapters_in_toc': False,
 'no_images': False,
 'no_inline_navbars': True,
 'no_inline_toc': False,
 'output_profile': <calibre.customize.profiles.KindlePaperWhiteOutput object at 0x00DAB210>,
 'page_breaks_before': u"//*[name()='h1' or name()='h2']",
 'personal_doc': u'[PDOC]',
 'prefer_author_sort': False,
 'prefer_metadata_cover': False,
 'pretty_print': False,
 'pubdate': None,
 'publisher': None,
 'rating': None,
 'read_metadata_from_opf': u'C:\\Users\\Student\\AppData\\Local\\Temp\\calibre_3nkkvk\\lylox9.opf',
 'remove_fake_margins': True,
 'remove_first_image': False,
 'remove_paragraph_spacing': False,
 'remove_paragraph_spacing_indent_size': 1.5,
 'renumber_headings': True,
 'replace_scene_breaks': u'',
 'search_replace': '[]',
 'series': None,
 'series_index': None,
 'share_not_sync': False,
 'smarten_punctuation': False,
 'sr1_replace': None,
 'sr1_search': None,
 'sr2_replace': None,
 'sr2_search': None,
 'sr3_replace': None,
 'sr3_search': None,
 'start_reading_at': None,
 'subset_embedded_fonts': False,
 'tags': None,
 'timestamp': None,
 'title': None,
 'title_sort': None,
 'toc_filter': None,
 'toc_threshold': 6,
 'toc_title': None,
 'transform_css_rules': '[]',
 'unsmarten_punctuation': False,
 'unwrap_factor': 0.45,
 'unwrap_lines': True,
 'use_auto_toc': False,
 'verbose': 2}
InputFormatPlugin: PDF Input running
on C:\Users\Student\AppData\Local\Temp\calibre_3nkkvk\s3kep0.pdf
Converting file to html...
Python function terminated unexpectedly
  pdftohtml failed with return code: 1
Internal Error: xref num 2905 not found but needed, try to reconstruct<0a>
Syntax Error: Couldn't find trailer dictionary
Syntax Error: Catalog object is wrong type (null)
Syntax Error: Couldn't find trailer dictionary
Syntax Error: Invalid XRef entry
Internal Error: xref num 2905 not found but needed, try to reconstruct<0a>
Syntax Error: Invalid XRef entry
Syntax Error: Couldn't find trailer dictionary
Syntax Error: Catalog object is wrong type (null)
Syntax Error: Couldn't read page catalog (Error Code: 1)
Traceback (most recent call last):
  File "site.py", line 101, in main
  File "site.py", line 78, in run_entry_point
  File "site-packages\calibre\utils\ipc\worker.py", line 195, in main
  File "site-packages\calibre\gui2\convert\gui_conversion.py", line 33, in gui_convert_override
  File "site-packages\calibre\gui2\convert\gui_conversion.py", line 26, in gui_convert
  File "site-packages\calibre\ebooks\conversion\plumber.py", line 1088, in run
  File "site-packages\calibre\customize\conversion.py", line 245, in __call__
  File "site-packages\calibre\ebooks\conversion\plugins\pdf_input.py", line 51, in convert
  File "site-packages\calibre\ebooks\pdf\pdftohtml.py", line 92, in pdftohtml
calibre.ebooks.ConversionError: pdftohtml failed with return code: 1
Internal Error: xref num 2905 not found but needed, try to reconstruct<0a>
Syntax Error: Couldn't find trailer dictionary
Syntax Error: Catalog object is wrong type (null)
Syntax Error: Couldn't find trailer dictionary
Syntax Error: Invalid XRef entry
Internal Error: xref num 2905 not found but needed, try to reconstruct<0a>
Syntax Error: Invalid XRef entry
Syntax Error: Couldn't find trailer dictionary
Syntax Error: Catalog object is wrong type (null)
Syntax Error: Couldn't read page catalog