Avianca Holdings listing on NYSE was halted by NYSE prior to the market opening on 11 Mar 2020 due to the announcement of the initiation of voluntary reorganization proceedings under Chapter 11 of the United States Bankruptcy Code. Trading in AVH has been halted on other US exchanges too.
During trading halts, all bids and asks are cleared and no trades can occur.
In situations like these, most companies rapidly lose their exchange listing and become OTC securities trading with a five letter symbol ending in "Q".
Past bankruptcy events
When General Motors (with common shares listed on NYSE) went declared bankruptcy it began trading the next day as GMGMQ as an OTC security.
When Oi SA (a Brazillian telecommunications company, with ADRs listed on NYSE under the symbol OIBR) declared bankruptcy in 2016, it was halted for one day before commencing trade as an OTC security.
When LDK Solar Co Ltd (a Chinese solar voltaic company, with ADRs listed on NYSE under the symbol LDK) declared bankruptcy in 2014, it took 5 weeks until it started trading again as an OTC security.
Likely resumption of trading
Since they are looking at a reorganization of the company it's likely that the ADR will resume trading as an OTC security, but there may be other regulations involved given the Colombia listing, plus other COVID-19-related delays.
Various databases at Norgate Data
SEC Filing/press for Avianca Holdings
Avianca Will Keep on Flying Website
Disclosure: I am a co-owner of Norgate Data.