Build Error in Fastpages

2020-04-22T16:42:52.3337009Z ##[section]Starting: Request a runner to run this job
2020-04-22T16:42:52.6504131Z Requesting a hosted runner in current repository's account/organization with labels: 'ubuntu-latest', require runner match: True
2020-04-22T16:42:52.7554344Z Labels matched hosted runners has been found, waiting for one of them get assigned for this job.
2020-04-22T16:42:52.7789636Z ##[section]Finishing: Request a runner to run this job
2020-04-22T16:42:57.4613085Z Current runner version: '2.169.0'
2020-04-22T16:42:57.4635921Z ##[group]Operating System
2020-04-22T16:42:57.4636901Z Ubuntu
2020-04-22T16:42:57.4637126Z 18.04.4
2020-04-22T16:42:57.4637353Z LTS
2020-04-22T16:42:57.4637539Z ##[endgroup]
2020-04-22T16:42:57.4637681Z ##[group]Virtual Environment
2020-04-22T16:42:57.4637895Z Environment: ubuntu-18.04
2020-04-22T16:42:57.4638100Z Version: 20200406.2
2020-04-22T16:42:57.4638374Z Included Software: https://github.com/actions/virtual-environments/blob/ubuntu18/20200406.2/images/linux/Ubuntu1804-README.md
2020-04-22T16:42:57.4638563Z ##[endgroup]
2020-04-22T16:42:57.4639541Z Prepare workflow directory
2020-04-22T16:42:57.4846645Z Prepare all required actions
2020-04-22T16:42:57.5352435Z ##[group]Run import os
2020-04-22T16:42:57.5352659Z import os
2020-04-22T16:42:57.5352791Z status, errormsg = os.getenv('STATUS'), os.getenv('ERROR')
2020-04-22T16:42:57.5352968Z assert status == 'built', 'There was an error building the page on GitHub pages.\n\nStatus: {}\n\nError messsage: {}'.format(status, errormsg)
2020-04-22T16:42:57.6970078Z shell: /usr/bin/python {0}
2020-04-22T16:42:57.6970720Z env:
2020-04-22T16:42:57.6970871Z   STATUS: errored
2020-04-22T16:42:57.6971132Z   ERROR: The tag `twitter` on line 86 in `_posts/2020-01-14-test-markdown-post.md` is not a recognized Liquid tag. For more information, see https://help.github.com/en/github/working-with-github-pages/troubleshooting-jekyll-build-errors-for-github-pages-sites#unknown-tag-error.
2020-04-22T16:42:57.6971471Z ##[endgroup]
2020-04-22T16:42:58.4271178Z Traceback (most recent call last):
2020-04-22T16:42:58.4272057Z   File "/home/runner/work/_temp/118b7e0b-81aa-49b4-b46f-9cbdf868b8ce.py", line 3, in <module>
2020-04-22T16:42:58.4272550Z     assert status == 'built', 'There was an error building the page on GitHub pages.\n\nStatus: {}\n\nError messsage: {}'.format(status, errormsg)
2020-04-22T16:42:58.4272749Z AssertionError: There was an error building the page on GitHub pages.
2020-04-22T16:42:58.4272887Z 
2020-04-22T16:42:58.4273030Z Status: errored
2020-04-22T16:42:58.4273105Z 
2020-04-22T16:42:58.4273766Z Error messsage: The tag `twitter` on line 86 in `_posts/2020-01-14-test-markdown-post.md` is not a recognized Liquid tag. For more information, see https://help.github.com/en/github/working-with-github-pages/troubleshooting-jekyll-build-errors-for-github-pages-sites#unknown-tag-error.
2020-04-22T16:42:58.4290749Z ##[error]Process completed with exit code 1.
2020-04-22T16:42:58.4320563Z Cleaning up orphan processes