On screen: The Rockstar Game Services are unavailable and offline play could not be verified (code 134). Please check your connection and try again later.
This error is produced locally. It does not appear because the service is down, so the fixes below are worth working through in order.
Read the number, not the sentence. Rockstar prints essentially the same wording for 133 and 134, but their documentation gives 134 a specific cause: the installed version of the game is out of date, so the server rejects the verification from an older client.
The message telling you to check your connection is therefore unhelpful here. Your connection is probably fine; your patch is not applied.
That makes this a likely day-one patch code. When an update ships and some people start on an unpatched install, this is what they get.
Compare your installed version against the current one. If a patch is pending or half-applied, that is your answer and no amount of network work will change it. If you are fully up to date and still see 134, treat it as 133 and check whether Rockstar's services are healthy.
Operator documentation: support.rockstargames.com. Worth knowing about this source. Rockstar publishes no index of error codes at all — we checked their support home, their search, which returns a 404, and their own Error Code category filter, which returns nine articles of which one is actually about an error code. Their pages exist but are findable only through outside search. They are the third major operator we have found doing this, after Sony and Twitch. Note also that third-party guides attribute 134 to outages, unstable connections and drivers. Rockstar attributes it to the game version and nothing else, so we are labelling the rest as community guesswork.
Read the number, not the sentence. Rockstar prints essentially the same wording for 133 and 134, but their documentation gives 134 a specific cause: the installed version of the game is out of date, so the server rejects the verification from an older client.
This error is produced locally. It does not appear because the service is down, so the fixes below are worth working through in order.
Start with: Verify the game files. In the Rockstar launcher use the verify option in the game's settings; on Steam use Verify Integrity of Game Files; on Epic use Verify. This catches the half-applied patch, which is the usual case.