# Error decoding header block: Encoder did not shrink table size to within the max

**URL:** <https://discourse.mitmproxy.org/t/error-decoding-header-block-encoder-did-not-shrink-table-size-to-within-the-max/1692>\
**Category:** help\
**Created:** [October 9, 2019, 2:38am UTC](https://discourse.mitmproxy.org/t/error-decoding-header-block-encoder-did-not-shrink-table-size-to-within-the-max/1692 "2019-10-09T02:38:26Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![lpcdma](https://avatars.discourse-cdn.com/v4/letter/l/13edae/32.png) [@lpcdma](https://discourse.mitmproxy.org/u/lpcdma)\
**Post date:** [October 9, 2019, 2:38am UTC](https://discourse.mitmproxy.org/t/error-decoding-header-block-encoder-did-not-shrink-table-size-to-within-the-max/1692/1 "2019-10-09T02:38:26Z")

</div>

Can only get such an error message!!!  
command args:./mitmweb --listen-port=7777 --web-iface 0.0.0.0 --set block\_global=false --set http2\_priority=true --set termlog\_verbosity=debug --set bodyize\_limit=3m  
debug info 🙂::ffff:127.0.0.1:39876: HTTP2 Event from server  
-\> \<SettingsAcknowledged changed\_settings:{ChangedSetting(setting=SettingCodes.HEADER\_TABLE\_SIZE, original\_value=4096, new\_value=0), ChangedSetting(setting=SettingCodes.ENABLE\_PUSH, original\_value=1, new\_value=0)}\>  
::ffff:127.0.0.1:39876: HTTP2 Event from client  
-\> \<SettingsAcknowledged changed\_settings:{ChangedSetting(setting=SettingCodes.MAX\_CONCURRENT\_STREAMS, original\_value=100, new\_value=20)}\>  
::ffff:127.0.0.1:39876: HTTP2 Event from client  
-\> \<SettingsAcknowledged changed\_settings:{}\>  
::ffff:127.0.0.1:39876: HTTP2 Event from server  
-\> \<SettingsAcknowledged changed\_settings:{}\>  
::ffff:127.0.0.1:39876: ProtocolError(‘Error decoding header block: Encoder did not shrink table size to within the max’,)  
::ffff:127.0.0.1:39876: serverdisconnect

usage C# Client send http/2.0 protocol  
C# error:System.IO.IOException : The response ended prematurely, with at least 9 additional bytes expected.  
Sorry, the full code and package could not be provided for confidentiality reasons  
The problem description is nothing more than thi