Try make sure to kill bitcoind in travis
MODIFY
.travis.yml
.travis.yml
@@ -23,6 +23,7 @@ cache:
before_install:
- if [ $TRAVIS_OS_NAME = osx ]; then ulimit -S -n 4096; fi
+ - sudo killall bitcoind
script:
- travis_wait dotnet test WalletWasabi.Tests/WalletWasabi.Tests.csproj --filter Category=RunOnCi

Try make sure to kill bitcoind in travis