A situation in which no progress can be made or no advancement is possible WordNet 3.0 & Open English WordNet

A bargaining impasse occurs when the two sides negotiating an agreement are unable to reach an agreement and become deadlocked. Wikipedia

In concurrent computing, deadlock is any situation in which no member of some group of entities can proceed because each waits for another member, including itself, to take action, such as sending a message or, more commonly, releasing a lock. Wikipedia

Breakdown in negotiations. Wikipedia Disambiguation

Situation in computing where two processes are each waiting for the other to finish. Wikipedia Disambiguation

State in which members are blocking each other Wikidata

Deadlock in negotiations Wikidata

A situation in which no progress can be made or no advancement is possible. OmegaWiki

A standstill resulting from the opposition of two evenly matched forces; a stalemate or impasse. Wiktionary

Standstill. Wiktionary (translation)

A deadlock or stalemate situation in which no progress can be made. Wiktionary

Deadlock or stalemate situation. Wiktionary (translation)