fix: explain transport host rejections #2362

Job	Run time
checks / readme-snippets	12s
checks / pre-commit	34s
checks / test (3.11, lowest-direct, windows-latest)	3m 2s
checks / test (3.10, lowest-direct, windows-latest)	2m 44s
checks / test (3.11, lowest-direct, ubuntu-latest)	1m 2s
checks / test (3.10, locked, windows-latest)	2m 7s
checks / test (3.12, locked, windows-latest)	3m 29s
checks / test (3.10, lowest-direct, ubuntu-latest)	1m 7s
checks / test (3.12, lowest-direct, windows-latest)	4m 18s
checks / test (3.11, locked, ubuntu-latest)	1m 0s
checks / test (3.13, lowest-direct, windows-latest)	3m 7s
checks / test (3.12, locked, ubuntu-latest)	1m 3s
checks / test (3.11, locked, windows-latest)	3m 27s
checks / test (3.13, lowest-direct, ubuntu-latest)	54s
checks / test (3.12, lowest-direct, ubuntu-latest)	1m 21s
checks / test (3.10, locked, ubuntu-latest)	1m 13s
checks / test (3.13, locked, ubuntu-latest)	59s
checks / test (3.13, locked, windows-latest)	2m 37s
checks / test (3.14, locked, ubuntu-latest)	2m 32s
checks / test (3.14, lowest-direct, ubuntu-latest)	1m 32s
checks / test (3.14, lowest-direct, windows-latest)	2m 35s
checks / test (3.14, locked, windows-latest)	3m 22s
all-green	2s
	44m 19s

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