Show error when failing to communicate with server
Show error when failing to communicate with server

Closes #949.

hudl/redash,imsally/redash,alexanderlz/redash,M32Media/redash,moritz9/redash,denisov-vlad/redash,akariv/redash,chriszs/redash,akariv/redash,ninneko/redash,alexanderlz/redash,rockwotj/redash,chriszs/redash,guaguadev/redash,hudl/redash,guaguadev/redash,getredash/redash,easytaxibr/redash,hudl/redash,44px/redash,getredash/redash,denisov-vlad/redash,imsally/redash,akariv/redash,easytaxibr/redash,44px/redash,akariv/redash,easytaxibr/redash,amino-data/redash,useabode/redash,vishesh92/redash,denisov-vlad/redash,ninneko/redash,amino-data/redash,denisov-vlad/redash,getredash/redash,easytaxibr/redash,imsally/redash,EverlyWell/redash,useabode/redash,stefanseifert/redash,hudl/redash,44px/redash,akariv/redash,ninneko/redash,rockwotj/redash,moritz9/redash,crowdworks/redash,chriszs/redash,alexanderlz/redash,EverlyWell/redash,guaguadev/redash,stefanseifert/redash,vishesh92/redash,useabode/redash,getredash/redash,crowdworks/redash,rockwotj/redash,getredash/redash,crowdworks/redash,easytaxibr/redash,amino-data/redash,chriszs/redash,moritz9/redash,stefanseifert/redash,guaguadev/redash,M32Media/redash,denisov-vlad/redash,useabode/redash,imsally/redash,alexanderlz/redash,stefanseifert/redash,EverlyWell/redash,rockwotj/redash,vishesh92/redash,guaguadev/redash,crowdworks/redash,stefanseifert/redash,M32Media/redash,moritz9/redash,44px/redash,ninneko/redash,ninneko/redash,amino-data/redash,EverlyWell/redash,vishesh92/redash,M32Media/redash